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JSON Functions And Operators
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<span class="fancy_toc_mark" id="toc_mk">►</span>
Table Of Contents
</a>
<div id="toc_sub"><div class="fancy-toc1"><a href="#overview">1. Overview</a></div>
<div class="fancy-toc1"><a href="#compiling_in_json_support">2. Compiling in JSON Support</a></div>
<div class="fancy-toc1"><a href="#interface_overview">3. Interface Overview</a></div>
<div class="fancy-toc2"><a href="#json_arguments">3.1. JSON arguments</a></div>
<div class="fancy-toc2"><a href="#jsonb">3.2. JSONB</a></div>
<div class="fancy-toc3"><a href="#the_jsonb_format">3.2.1. The JSONB format</a></div>
<div class="fancy-toc3"><a href="#handling_of_malformed_jsonb">3.2.2. Handling of malformed JSONB</a></div>
<div class="fancy-toc2"><a href="#path_arguments">3.3. PATH arguments</a></div>
<div class="fancy-toc2"><a href="#value_arguments">3.4. VALUE arguments</a></div>
<div class="fancy-toc2"><a href="#compatibility">3.5. Compatibility</a></div>
<div class="fancy-toc2"><a href="#json5_extensions">3.6. JSON5 Extensions</a></div>
<div class="fancy-toc2"><a href="#performance_considerations">3.7. Performance Considerations</a></div>
<div class="fancy-toc2"><a href="#the_json_blob_input_bug">3.8. The JSON BLOB Input Bug</a></div>
<div class="fancy-toc1"><a href="#function_details">4. Function Details</a></div>
<div class="fancy-toc2"><a href="#the_json_function">4.1. The json() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_function">4.2. The jsonb() function</a></div>
<div class="fancy-toc2"><a href="#the_json_array_function">4.3. The json_array() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_array_function">4.4. The jsonb_array() function</a></div>
<div class="fancy-toc2"><a href="#the_json_array_length_function">4.5. The json_array_length() function</a></div>
<div class="fancy-toc2"><a href="#the_json_error_position_function">4.6. The json_error_position() function</a></div>
<div class="fancy-toc2"><a href="#the_json_extract_function">4.7. The json_extract() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_extract_function">4.8. The jsonb_extract() function</a></div>
<div class="fancy-toc2"><a href="#the_and_operators">4.9. The -> and ->> operators</a></div>
<div class="fancy-toc2"><a href="#the_json_insert_json_replace_and_json_set_functions">4.10. The json_insert(), json_replace, and json_set() functions</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_insert_jsonb_replace_and_jsonb_set_functions">4.11. The jsonb_insert(), jsonb_replace, and jsonb_set() functions</a></div>
<div class="fancy-toc2"><a href="#the_json_object_function">4.12. The json_object() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_object_function">4.13. The jsonb_object() function</a></div>
<div class="fancy-toc2"><a href="#the_json_patch_function">4.14. The json_patch() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_patch_function">4.15. The jsonb_patch() function</a></div>
<div class="fancy-toc2"><a href="#the_json_pretty_function">4.16. The json_pretty() function</a></div>
<div class="fancy-toc2"><a href="#the_json_remove_function">4.17. The json_remove() function</a></div>
<div class="fancy-toc2"><a href="#the_jsonb_remove_function">4.18. The jsonb_remove() function</a></div>
<div class="fancy-toc2"><a href="#the_json_type_function">4.19. The json_type() function</a></div>
<div class="fancy-toc2"><a href="#the_json_valid_function">4.20. The json_valid() function</a></div>
<div class="fancy-toc2"><a href="#the_json_quote_function">4.21. The json_quote() function</a></div>
<div class="fancy-toc2"><a href="#array_and_object_aggregate_functions">4.22. Array and object aggregate functions</a></div>
<div class="fancy-toc2"><a href="#the_json_each_and_json_tree_table_valued_functions">4.23. The json_each() and json_tree() table-valued functions</a></div>
<div class="fancy-toc3"><a href="#examples_using_json_each_and_json_tree_">4.23.1. Examples using json_each() and json_tree()</a></div>
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<h1 id="overview"><span>1. </span>Overview</h1>
<p>
By default, SQLite supports thirty functions and two operators for
dealing with JSON values. There are also two <a href="vtab.html#tabfunc2">table-valued functions</a>
that can be used to decompose a JSON string.
</p><p>
There are twenty-six scalar functions and operators:
</p><ol>
<li value='1'>
<a href='#jmini'>json</a>(<i>json</i>)
</li>
<li value='2'>
<a href='#jminib'>jsonb</a>(<i>json</i>)
</li>
<li value='3'>
<a href='#jarray'>json_array</a>(<i>value1</i>,<i>value2</i>,...)
</li>
<li value='4'>
<a href='#jarrayb'>jsonb_array</a>(<i>value1</i>,<i>value2</i>,...)
</li>
<li value='5'>
<a href='#jarraylen'>json_array_length</a>(<i>json</i>)<br><a href='#jarraylen'>json_array_length</a>(<i>json</i>,<i>path</i>)
</li>
<li value='6'>
<a href='#jerr'>json_error_position</a>(<i>json</i>)
</li>
<li value='7'>
<a href='#jex'>json_extract</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='8'>
<a href='#jexb'>jsonb_extract</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='9'>
<i>json</i> <a href='#jptr'>-></a> <i>path</i>
</li>
<li value='10'>
<i>json</i> <a href='#jptr'>->></a> <i>path</i>
</li>
<li value='11'>
<a href='#jins'>json_insert</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='12'>
<a href='#jinsb'>jsonb_insert</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='13'>
<a href='#jobj'>json_object</a>(<i>label1</i>,<i>value1</i>,...)
</li>
<li value='14'>
<a href='#jobjb'>jsonb_object</a>(<i>label1</i>,<i>value1</i>,...)
</li>
<li value='15'>
<a href='#jpatch'>json_patch</a>(<i>json</i>1,json2)
</li>
<li value='16'>
<a href='#jpatchb'>jsonb_patch</a>(<i>json</i>1,json2)
</li>
<li value='17'>
<a href='#jpretty'>json_pretty</a>(<i>json</i>)
</li>
<li value='18'>
<a href='#jrm'>json_remove</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='19'>
<a href='#jrmb'>jsonb_remove</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='20'>
<a href='#jrepl'>json_replace</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='21'>
<a href='#jreplb'>jsonb_replace</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='22'>
<a href='#jset'>json_set</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='23'>
<a href='#jsetb'>jsonb_set</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='24'>
<a href='#jtype'>json_type</a>(<i>json</i>)<br><a href='#jtype'>json_type</a>(<i>json</i>,<i>path</i>)
</li>
<li value='25'>
<a href='#jvalid'>json_valid</a>(<i>json</i>)<br><a href='#jvalid'>json_valid</a>(<i>json</i>,flags)
</li>
<li value='26'>
<a href='#jquote'>json_quote</a>(<i>value</i>)
</li>
</ol>
<p>There are four <a href="lang_aggfunc.html">aggregate SQL functions</a>:
</p><ol>
<li value='27'>
<a href='#jgrouparray'>json_group_array</a>(<i>value</i>)
</li>
<li value='28'>
<a href='#jgrouparrayb'>jsonb_group_array</a>(<i>value</i>)
</li>
<li value='29'>
<a href='#jgroupobject'>json_group_object</a>(<i>label</i>,<i>value</i>)
</li>
<li value='30'>
<a href='#jgroupobjectb'>jsonb_group_object</a>(name,<i>value</i>)
</li>
</ol>
<p>The two <a href="vtab.html#tabfunc2">table-valued functions</a> are:
</p><ol>
<li value='31'>
<a href='#jeach'>json_each</a>(<i>json</i>)<br><a href='#jeach'>json_each</a>(<i>json</i>,<i>path</i>)
</li>
<li value='32'>
<a href='#jtree'>json_tree</a>(<i>json</i>)<br><a href='#jtree'>json_tree</a>(<i>json</i>,<i>path</i>)
</li>
</ol>
<style>
.jans {color: #050;}
.jex {color: #025;}
</style>
<a name="howtocompile"></a>
<h1 id="compiling_in_json_support"><span>2. </span>Compiling in JSON Support</h1>
<p>
The JSON functions and operators are built into SQLite by default,
as of SQLite version 3.38.0 (2022-02-22). They can be omitted
by adding the -DSQLITE_OMIT_JSON compile-time option. Prior to
version 3.38.0, the JSON functions were an extension that would only
be included in builds if the -DSQLITE_ENABLE_JSON1 compile-time option
was included. In other words, the JSON functions went from being
opt-in with SQLite version 3.37.2 and earlier to opt-out with
SQLite version 3.38.0 and later.
</p><h1 id="interface_overview"><span>3. </span>Interface Overview</h1>
<p>
SQLite stores JSON as ordinary text.
Backwards compatibility constraints mean that SQLite is only able to
store values that are NULL, integers, floating-point numbers, text,
and BLOBs. It is not possible to add a new "JSON" type.
</p><h2 id="json_arguments"><span>3.1. </span>JSON arguments</h2>
<p>
For functions that accept JSON as their first argument, that argument
can be a JSON object, array, number, string, or null. SQLite numeric
values and NULL values are interpreted as JSON numbers and nulls, respectively.
SQLite text values can be understood as JSON objects, arrays, or strings.
If an SQLite text value that is not a well-formed JSON object, array, or
string is passed into JSON function, that function will usually throw
an error. (Exceptions to this rule are <a href="json1.html#jvalid">json_valid()</a>,
<a href="json1.html#jquote">json_quote()</a>, and <a href="json1.html#jerr">json_error_position()</a>.)
</p><p>
These routines understand all
<a href="https://www.rfc-editor.org/rfc/rfc8259.txt">rfc-8259 JSON syntax</a>
and also <a href="https://spec.json5.org/">JSON5 extensions</a>. JSON text
generated by these routines always strictly conforms to the
<a href="https://json.org">canonical JSON definition</a> and does not contain any JSON5
or other extensions. The ability to read and understand JSON5 was added in
version 3.42.0 (2023-05-16).
Prior versions of SQLite would only read canonical JSON.
<a name="jsonbx"></a>
</p><h2 id="jsonb"><span>3.2. </span>JSONB</h2>
<p>
Beginning with version 3.45.0 (2024-01-15), SQLite allows its
internal "parse tree" representation of JSON to be stored on disk,
as a BLOB, in a format that we call "JSONB". By storing SQLite's internal
binary representation of JSON directly in the database, applications
can bypass the overhead of parsing and rendering JSON when reading and
updating JSON values. The internal JSONB format also uses slightly
less disk space then text JSON.
</p><p>
Any SQL function parameter that accepts text JSON as an input will also
accept a BLOB in the JSONB format. The function will operate the
same in either case, except that it will run faster when
the input is JSONB, since it does not need to run the JSON parser.
</p><p>
Most SQL functions that return JSON text have a corresponding function
that returns the equivalent JSONB. The functions that return JSON
in the text format begin with "<tt>json_</tt>" and functions that
return the binary JSONB format begin with "<tt>jsonb_</tt>".
</p><h3 id="the_jsonb_format"><span>3.2.1. </span>The JSONB format</h3>
<p>
JSONB is a binary representation of JSON used by SQLite and
is intended for internal use by SQLite only. Applications
should not use JSONB outside of SQLite nor try to reverse-engineer the
JSONB format.
</p><p>
The "JSONB" name is inspired by <a href="https://postgresql.org">PostgreSQL</a>, but the
on-disk format for SQLite's JSONB is not the same as PostgreSQL's.
The two formats have the same name, but are not binary compatible.
The PostgreSQL JSONB format claims to offer O(1)
lookup of elements in objects and arrays. SQLite's JSONB format makes no
such claim. SQLite's JSONB has O(N) time complexity for
most operations in SQLite, just like text JSON. The advantage of JSONB in
SQLite is that it is smaller and faster than text JSON - potentially several
times faster. There is space in the
on-disk JSONB format to add enhancements and future versions of SQLite might
include options to provide O(1) lookup of elements in JSONB, but no such
capability is currently available.
</p><h3 id="handling_of_malformed_jsonb"><span>3.2.2. </span>Handling of malformed JSONB</h3>
<p>
The JSONB that is generated by SQLite will always be well-formed. If you
follow recommended practice and
treat JSONB as an opaque BLOB, then you will not have any problems. But
JSONB is just a BLOB, so a mischievous programmer could devise BLOBs
that are similar to JSONB but that are technically malformed. When
misformatted JSONB is feed into JSON functions, any of the following
might happen:
</p><ul>
<li><p>
The SQL statement might abort with a "malformed JSON" error.
</p></li><li><p>
The correct answer might be returned, if the malformed parts of
the JSONB blob do not impact the answer.
</p></li><li><p>
A goofy or nonsensical answer might be returned.
</p></li></ul>
<p>
The way in which SQLite handles invalid JSONB might change
from one version of SQLite to the next. The system follows
the garbage-in/garbage-out rule: If you feed the JSON functions invalid
JSONB, you get back an invalid answer. If you are in doubt about the
validity of our JSONB, use the <a href="json1.html#jvalid">json_valid()</a> function to verify it.
</p><p>
We do make this one promise:
Malformed JSONB will never cause a memory
error or similar problem that might lead to a vulnerability.
Invalid JSONB might lead to crazy answers,
or it might cause queries to abort, but it won't cause a crash.
<a name="jsonpath"></a>
</p><h2 id="path_arguments"><span>3.3. </span>PATH arguments</h2>
<p>
For functions that accept PATH arguments, that PATH must be well-formed or
else the function will throw an error.
A well-formed PATH is a text value that begins with exactly one
'$' character followed by zero or more instances
of ".<i>objectlabel</i>" or "[<i>arrayindex</i>]".
</p><p>
The <i>arrayindex</i> is usually a non-negative integer <i>N</i>. In
that case, the array element selected is the <i>N</i>-th element
of the array, starting with zero on the left.
The <i>arrayindex</i> can also be of the form "<b>#-</b><i>N</i>"
in which case the element selected is the <i>N</i>-th from the
right. The last element of the array is "<b>#-1</b>". Think of
the "#" characters as the "number of elements in the array". Then
the expression "#-1" evaluates to the integer that corresponds to
the last entry in the array. It is sometimes useful for the array
index to be just the <b>#</b> character, for example when appending
a value to an existing JSON array:
<ul>
<li><span class='jex'>json_set('[0,1,2]','$[#]','new')</span>
<span class='jans'>→ '[0,1,2,"new"]'</span></li>
</ul>
<a name="varg"></a>
</p><h2 id="value_arguments"><span>3.4. </span>VALUE arguments</h2>
<p>
For functions that accept "<i>value</i>" arguments (also shown as
"<i>value1</i>" and "<i>value2</i>"),
those arguments are usually understood
to be literal strings that are quoted and become JSON string values
in the result. Even if the input <i>value</i> strings look like
well-formed JSON, they are still interpreted as literal strings in the
result.
</p><p>
However, if a <i>value</i> argument comes directly from the result of another
JSON function or from <a href="json1.html#jptr">the -> operator</a> (but not <a href="json1.html#jptr">the ->> operator</a>),
then the argument is understood to be actual JSON and
the complete JSON is inserted rather than a quoted string.
</p><p>
For example, in the following call to json_object(), the <i>value</i>
argument looks like a well-formed JSON array. However, because it is just
ordinary SQL text, it is interpreted as a literal string and added to the
result as a quoted string:
<ul>
<li><span class='jex'>json_object('ex','[52,3.14159]')</span>
<span class='jans'>→ '{"ex":"[52,3.14159]"}'</span></li>
<li><span class='jex'>json_object('ex',('[52,3.14159]'->>'$'))</span>
<span class='jans'>→ '{"ex":"[52,3.14159]"}'</span></li>
</ul>
</p><p>
But if the <i>value</i> argument in the outer json_object() call is the
result of another JSON function like <a href="json1.html#jmini">json()</a> or <a href="json1.html#jarray">json_array()</a>, then
the value is understood to be actual JSON and is inserted as such:
<ul>
<li><span class='jex'>json_object('ex',json('[52,3.14159]'))</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
<li><span class='jex'>json_object('ex',json_array(52,3.14159))</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
<li><span class='jex'>json_object('ex','[52,3.14159]'->'$')</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
</ul>
</p><p>
To be clear: "<i>json</i>" arguments are always interpreted as JSON
regardless of where the value for that argument comes from. But
"<i>value</i>" arguments are only interpreted as JSON if those arguments
come directly from another JSON function or <a href="json1.html#jptr">the -> operator</a>.
</p><p>
Within JSON value arguments interpreted as JSON strings, Unicode escape
sequences are not treated as equivalent to the characters or escaped
control characters represented by the expressed Unicode code point.
Such escape sequences are not translated or specially treated; they
are treated as plain text by SQLite's JSON functions.
</p><h2 id="compatibility"><span>3.5. </span>Compatibility</h2>
<p>
The current implementation of this JSON library uses a recursive descent
parser. In order to avoid using excess stack space, any JSON input that has
more than 1000 levels of nesting is considered invalid. Limits on nesting
depth are allowed for compatible implementations of JSON by
<a href="https://tools.ietf.org/html/rfc8259#section-9">RFC-8259 section 9</a>.
<a name="json5"></a>
</p><h2 id="json5_extensions"><span>3.6. </span>JSON5 Extensions</h2>
<p>
Beginning in version 3.42.0 (2023-05-16), these routines will
read and interpret input JSON text that includes
<a href="https://spec.json5.org/">JSON5</a> extensions. However, JSON text generated
by these routines will always be strictly conforming to the
<a href="https://json.org">canonical definition of JSON</a>.
</p><p>
Here is a synopsis of JSON5 extensions (adapted from the
<a href="https://spec.json5.org/#introduction">JSON5 specification</a>):
</p><ul>
<li> Object keys may be unquoted identifiers.
</li><li> Objects may have a single trailing comma.
</li><li> Arrays may have a single trailing comma.
</li><li> Strings may be single quoted.
</li><li> Strings may span multiple lines by escaping new line characters.
</li><li> Strings may include new character escapes.
</li><li> Numbers may be hexadecimal.
</li><li> Numbers may have a leading or trailing decimal point.
</li><li> Numbers may be "Infinity", "-Infinity", and "NaN".
</li><li> Numbers may begin with an explicit plus sign.
</li><li> Single (//...) and multi-line (/*...*/) comments are allowed.
</li><li> Additional white space characters are allowed.
</li></ul>
<p>
To convert string X from JSON5 into canonical JSON, invoke
"<a href="json1.html#jmini">json(X)</a>". The output of the "<a href="json1.html#jmini">json()</a>" function will be canonical
JSON regardless of any JSON5 extensions that are present in the input.
For backwards compatibility, the <a href="json1.html#jvalid">json_valid(X)</a> function without a
"flags" argument continues
to report false for inputs that are not canonical JSON, even if the
input is JSON5 that the function is able to understand. To determine
whether or not an input string is valid JSON5, include the 0x02 bit
in the "flags" argument to json_valid: "<tt>json_valid(X,2)</tt>".
</p><p>
These routines understand all of JSON5, plus a little more.
SQLite extends the JSON5 syntax in these two ways:
</p><ol>
<li><p>
Strict JSON5 requires that
unquoted object keys must be ECMAScript 5.1 IdentifierNames. But large
unicode tables and lots of code is required in order to determine whether or
not a key is an ECMAScript 5.1 IdentifierName. For this reason,
SQLite allows object keys to include any unicode characters
greater than U+007f that are not whitespace characters. This relaxed
definition of "identifier" greatly simplifies the implementation and allows
the JSON parser to be smaller and run faster.
</p></li><li><p>
JSON5 allows floating-point infinities to be expressed as
"<tt>Infinity</tt>", "<tt>-Infinity</tt>", or "<tt>+Infinity</tt>"
in exactly that case - the initial "I" is capitalized and all other
characters are lower case. SQLite also allows the abbreviation "<tt>Inf</tt>"
to be used in place of "<tt>Infinity</tt>" and it allows both keywords
to appear in any combination of upper and lower case letters.
Similarly,
JSON5 allows "NaN" for not-a-number. SQLite extends this to also allow
"QNaN" and "SNaN" in any combination of upper and lower case letters.
Note that SQLite interprets NaN, QNaN, and SNaN as just an alternative
spellings for "null".
This extension has been added because (we are told) there exists a lot
of JSON in the wild that includes these non-standard representations
for infinity and not-a-number.
</p></li></ol>
<h2 id="performance_considerations"><span>3.7. </span>Performance Considerations</h2>
<p>
Most JSON functions do their internal processing using JSONB. So if the
input is text, they first most translate the input text into JSONB.
If the input is already in the JSONB format, no translation is needed,
that step can be skipped, and performance is faster.
</p><p>
For that reason,
when an argument to one JSON function is supplied by another
JSON function, it is usually more efficient to use the "<tt>jsonb_</tt>"
variant for the function used as the argument.
</p><ul>
<li>
<tt>... json_insert(A,'$.b',json(C)) ...</tt>
← Less efficient.
</li><li>
<tt>... json_insert(A,'$.b',jsonb(C)) ...</tt>
← More efficient.
</li></ul>
<p>
The <a href="json1.html#jgroupobjectb">aggregate JSON SQL functions</a> are an exception to this rule. Those
functions all do their processing using text instead of JSONB. So for the
aggregate JSON SQL functions, it is more efficient for the arguments
to be supplied using "<tt>json_</tt>" functions than "<tt>jsonb_</tt>"
functions.
</p><ul>
<li>
<tt>... json_group_array(json(A))) ...</tt>
← More efficient.
</li><li>
<tt>... json_group_array(jsonb(A))) ...</tt>
← Less efficient.
</li></ul>
<a name="jblobbug"></a>
<h2 id="the_json_blob_input_bug"><span>3.8. </span>The JSON BLOB Input Bug</h2>
<p>If a JSON input is a BLOB that is not JSONB and that looks like
text JSON when cast to text, then it is accepted as text JSON.
This is actually a long-standing bug in the original implementation
that the SQLite developers were unaware of. The documentation stated
that a BLOB input to a JSON function should raise an error. But in the
actual implementation, the input would be accepted as long
as the BLOB content was a valid JSON string in the text encoding of
the database.
</p><p>This JSON BLOB input bug was accidentally fixed when the JSON routines
were reimplemented for the 3.45.0 release (2024-01-15).
That caused breakage in applications that had come to depend on the old
behavior. (In defense of those applications: they were often lured into
using BLOBs as JSON by the <a href="cli.html#fileio">readfile()</a> SQL function
available in the <a href="cli.html">CLI</a>. Readfile() was used to read JSON from disk files,
but readfile() returns a BLOB. And that worked for them, so why not just
do it?)
</p><p>For backwards compatibility,
the (formerly incorrect) legacy behavior of interpreting BLOBs as text JSON
if no other interpretation works
is hereby documented and is be officially supported in
version 3.45.1 (2024-01-30) and all subsequent releases.
</p><h1 id="function_details"><span>4. </span>Function Details</h1>
<p>The following sections provide additional detail on the operation of
the various JSON functions and operators:
<a name="jmini"></a>
</p><h2 id="the_json_function"><span>4.1. </span>The json() function</h2>
<p>The json(X) function verifies that its argument X is a valid
JSON string or JSONB blob and returns a minified version of that JSON string
with all unnecessary whitespace removed. If X is not a well-formed
JSON string or JSONB blob, then this routine throws an error.
</p><p>If the input is JSON5 text, then it is converted into canonical
RFC-8259 text prior to being returned.
</p><p>If the argument X to json(X) contains JSON objects with duplicate
labels, then it is undefined whether or not the duplicates are
preserved. The current implementation preserves duplicates.
However, future enhancements
to this routine may choose to silently remove duplicates.
</p><p>
Example:
<ul>
<li><span class='jex'>json(' { "this" : "is", "a": [ "test" ] } ')</span>
<span class='jans'>→ '{"this":"is","a":["test"]}'</span></li>
</ul>
<a name="jminib"></a>
</p><h2 id="the_jsonb_function"><span>4.2. </span>The jsonb() function</h2>
<p>The jsonb(X) function returns the binary JSONB representation
of the JSON provided as argument X. An error is raised if X is
TEXT that does not have valid JSON syntax.
</p><p>If X is a BLOB and appears to be JSONB,
then this routine simply returns a copy of X.
Only the outer-most element of the JSONB input is examined, however.
The deep structure of the JSONB is not validated.
<a name="jarray"></a>
</p><h2 id="the_json_array_function"><span>4.3. </span>The json_array() function</h2>
<p>The json_array() SQL function accepts zero or more arguments and
returns a well-formed JSON array that is composed from those arguments.
If any argument to json_array() is a BLOB then an error is thrown.
</p><p>An argument with SQL type TEXT is normally converted into a quoted
JSON string. However, if the argument is the output from another json1
function, then it is stored as JSON. This allows calls to json_array()
and <a href="json1.html#jobj">json_object()</a> to be nested. The <a href="json1.html#jmini">json()</a> function can also
be used to force strings to be recognized as JSON.
</p><p>Examples:
<ul>
<li><span class='jex'>json_array(1,2,'3',4)</span>
<span class='jans'>→ '[1,2,"3",4]'</span></li>
<li><span class='jex'>json_array('[1,2]')</span>
<span class='jans'>→ '["[1,2]"]'</span></li>
<li><span class='jex'>json_array(json_array(1,2))</span>
<span class='jans'>→ '[[1,2]]'</span></li>
<li><span class='jex'>json_array(1,null,'3','[4,5]','{"six":7.7}')</span>
<span class='jans'>→ '[1,null,"3","[4,5]","{\"six\":7.7}"]'</span></li>
<li><span class='jex'>json_array(1,null,'3',json('[4,5]'),json('{"six":7.7}'))</span>
<span class='jans'>→ '[1,null,"3",[4,5],{"six":7.7}]'</span></li>
</ul>
<a name="jarrayb"></a>
</p><h2 id="the_jsonb_array_function"><span>4.4. </span>The jsonb_array() function</h2>
<p>The jsonb_array() SQL function works just like the <a href="json1.html#jarray">json_array()</a>
function except that it returns the constructed JSON array in the
SQLite's private JSONB format rather than in the standard
RFC 8259 text format.
<a name="jarraylen"></a>
</p><h2 id="the_json_array_length_function"><span>4.5. </span>The json_array_length() function</h2>
<p>The json_array_length(X) function returns the number of elements
in the JSON array X, or 0 if X is some kind of JSON value other
than an array. The json_array_length(X,P) locates the array at path P
within X and returns the length of that array, or 0 if path P locates
an element in X that is not a JSON array, and NULL if path P does not
locate any element of X. Errors are thrown if either X is not
well-formed JSON or if P is not a well-formed path.
</p><p>Examples:
<ul>
<li><span class='jex'>json_array_length('[1,2,3,4]')</span>
<span class='jans'>→ 4</span></li>
<li><span class='jex'>json_array_length('[1,2,3,4]', '$')</span>
<span class='jans'>→ 4</span></li>
<li><span class='jex'>json_array_length('[1,2,3,4]', '$[2]')</span>
<span class='jans'>→ 0</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}')</span>
<span class='jans'>→ 0</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}', '$.one')</span>
<span class='jans'>→ 3</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}', '$.two')</span>
<span class='jans'>→ NULL</span></li>
</ul>
<a name="jerr"></a>
</p><h2 id="the_json_error_position_function"><span>4.6. </span>The json_error_position() function</h2>
<p>The json_error_position(X) function returns 0 if the input X is a
well-formed JSON or JSON5 string. If the input X contains one or more
syntax errors, then this function returns the character position of the
first syntax error. The left-most character is position 1.
</p><p>If the input X is a BLOB, then this routine returns 0 if X is
a well-formed JSONB blob. If the return value is positive, then it
represents the <i>approximate</i> 1-based position in the BLOB of the
first detected error.
</p><p>
The json_error_position() function was added with
SQLite version 3.42.0 (2023-05-16).
<a name="jex"></a>
</p><h2 id="the_json_extract_function"><span>4.7. </span>The json_extract() function</h2>
<p>The json_extract(X,P1,P2,...) extracts and returns one or more
values from the
well-formed JSON at X. If only a single path P1 is provided, then the
SQL datatype of the result is NULL for a JSON null, INTEGER or REAL
for a JSON numeric value, an INTEGER zero for a JSON false value,
an INTEGER one for a JSON true value, the dequoted text for a
JSON string value, and a text representation for JSON object and array values.
If there are multiple path arguments (P1, P2, and so forth) then this
routine returns SQLite text which is a well-formed JSON array holding
the various values.
</p><p>Examples:
<ul>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$')</span>
<span class='jans'>→ '{"a":2,"c":[4,5,{"f":7}]}'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c')</span>
<span class='jans'>→ '[4,5,{"f":7}]'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c[2]')</span>
<span class='jans'>→ '{"f":7}'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c[2].f')</span>
<span class='jans'>→ 7</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5],"f":7}','$.c','$.a')</span>
<span class='jans'>→ '[[4,5],2]'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5],"f":7}','$.c[#-1]')</span>
<span class='jans'>→ 5</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.x')</span>
<span class='jans'>→ NULL</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.x', '$.a')</span>
<span class='jans'>→ '[null,2]'</span></li>
<li><span class='jex'>json_extract('{"a":"xyz"}', '$.a')</span>
<span class='jans'>→ 'xyz'</span></li>
<li><span class='jex'>json_extract('{"a":null}', '$.a')</span>
<span class='jans'>→ NULL</span></li>
</ul>
</p><p>There is a subtle incompatibility between the json_extract() function
in SQLite and the json_extract() function in MySQL. The MySQL version
of json_extract() always returns JSON. The SQLite version of
json_extract() only returns JSON if there are two or more PATH arguments
(because the result is then a JSON array) or if the single PATH argument
references an array or object. In SQLite, if json_extract() has only
a single PATH argument and that PATH references a JSON null or a string
or a numeric value, then json_extract() returns the corresponding SQL
NULL, TEXT, INTEGER, or REAL value.
</p><p>The difference between MySQL json_extract() and SQLite json_extract()
really only stands out when accessing individual values within the JSON
that are strings or NULLs. The following table demonstrates the difference:
</p><center>
<table border="1" cellpadding="3" cellspacing="0">
<tr><th>Operation</th><th>SQLite Result</th><th>MySQL Result
</th></tr><tr><td>json_extract('{"a":null,"b":"xyz"}','$.a')</td><td>NULL</td><td>'null'
</td></tr><tr><td>json_extract('{"a":null,"b":"xyz"}','$.b')</td><td>'xyz'</td><td>'"xyz"'
</td></tr></table></center>
<a name="jexb"></a>
<h2 id="the_jsonb_extract_function"><span>4.8. </span>The jsonb_extract() function</h2>
<p>
The jsonb_extract() function works the same as the <a href="json1.html#jex">json_extract()</a> function,
except in cases where json_extract() would normally return a text
JSON array object, this routine returns the array or object in the
JSONB format. For the common case where a text, numeric, null, or
boolean JSON element is returned, this routine works exactly the same
as json_extract().
<a name="jptr"></a>
</p><h2 id="the_and_operators"><span>4.9. </span>The -> and ->> operators</h2>
<p>Beginning with SQLite version 3.38.0 (2022-02-22), the ->
and ->> operators are available for extracting subcomponents of JSON.
The SQLite implementation of -> and ->> strives to be
compatible with both MySQL and PostgreSQL.
The -> and ->> operators take a JSON string or JSONB blob
as their left operand and a PATH expression or object field
label or array index as their right operand. The -> operator
returns a text JSON representation of the selected subcomponent or
NULL if that subcomponent does not exist. The ->> operator returns
an SQL TEXT, INTEGER, REAL, or NULL value that represents the selected
subcomponent, or NULL if the subcomponent does not exist.
</p><p>Both the -> and ->> operators select the same subcomponent
of the JSON to their left. The difference is that -> always returns a
JSON representation of that subcomponent and the ->> operator always
returns an SQL representation of that subcomponent. Thus, these operators
are subtly different from a two-argument <a href="json1.html#jex">json_extract()</a> function call.
A call to json_extract() with two arguments will return a JSON representation
of the subcomponent if and only if the subcomponent is a JSON array or
object, and will return an SQL representation of the subcomponent if the
subcomponent is a JSON null, string, or numeric value.
</p><p>When the -> operator returns JSON, it always returns the
RFC 8565 text representation of that JSON, not JSONB. Use the
<a href="json1.html#jexb">jsonb_extract()</a> function if you need a subcomponent in the
JSONB format.
</p><p>The right-hand operand to the -> and ->> operators can
be a well-formed JSON path expression. This is the form used by MySQL.
For compatibility with PostgreSQL,
the -> and ->> operators also accept a text object label or
integer array index as their right-hand operand.
If the right operand is a text
label X, then it is interpreted as the JSON path '$.X'. If the right
operand is an integer value N, then it is interpreted as the JSON path '$[N]'.
</p><p>Examples:
<ul>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$'</span>