From b438bce9498321d67b02307c3f831dd9a01afc8e Mon Sep 17 00:00:00 2001
From: Jason Fowler <phalacee@gmail.com>
Date: Wed, 5 Oct 2011 16:20:50 +0800
Subject: [PATCH 1/2] MDL-29496 Search, Course - Code applied from patch to
 allow courses with a blank summary to be found in searchs - Thanks to Andrew
 Nicols for the patch

---
 lib/datalib.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/datalib.php b/lib/datalib.php
index 478156cd71232..503462708fb3c 100644
--- a/lib/datalib.php
+++ b/lib/datalib.php
@@ -717,7 +717,7 @@ function get_courses_search($searchterms, $sort='fullname ASC', $page=0, $record
     $params     = array();
     $i = 0;
 
-    $concat = $DB->sql_concat('c.summary', "' '", 'c.fullname', "' '", 'c.idnumber', "' '", 'c.shortname');
+    $concat = $DB->sql_concat("COALESCE(c.summary, ". $DB->sql_empty() .")", "' '", 'c.fullname', "' '", 'c.idnumber', "' '", 'c.shortname');
 
     foreach ($searchterms as $searchterm) {
         $i++;

From fc0aebb595ce50210b97cb1946b149f1be1b6180 Mon Sep 17 00:00:00 2001
From: "Eloy Lafuente (stronk7)" <stronk7@moodle.org>
Date: Mon, 17 Oct 2011 13:07:28 +0200
Subject: [PATCH 2/2] MDL-29496 unittests - verify COALESCE() cross-db
 compatibility

---
 lib/dml/simpletest/testdml.php | 42 ++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/lib/dml/simpletest/testdml.php b/lib/dml/simpletest/testdml.php
index 5f37e105dee55..8428fec2c2810 100644
--- a/lib/dml/simpletest/testdml.php
+++ b/lib/dml/simpletest/testdml.php
@@ -3378,6 +3378,48 @@ function test_sql_ilike() {
         $DB->get_records_sql($sql, $params);
     }
 
+    function test_coalesce() {
+        $DB = $this->tdb;
+
+        // Testing not-null ocurrences, return 1st
+        $sql = "SELECT COALESCE('returnthis', 'orthis', 'orwhynotthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array()));
+        $sql = "SELECT COALESCE(:paramvalue, 'orthis', 'orwhynotthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array('paramvalue' => 'returnthis')));
+
+        // Testing null ocurrences, return 2nd
+        $sql = "SELECT COALESCE(null, 'returnthis', 'orthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array()));
+        $sql = "SELECT COALESCE(:paramvalue, 'returnthis', 'orthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array('paramvalue' => null)));
+        $sql = "SELECT COALESCE(null, :paramvalue, 'orthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array('paramvalue' => 'returnthis')));
+
+        // Testing null ocurrences, return 3rd
+        $sql = "SELECT COALESCE(null, null, 'returnthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array()));
+        $sql = "SELECT COALESCE(null, :paramvalue, 'returnthis') AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array('paramvalue' => null)));
+        $sql = "SELECT COALESCE(null, null, :paramvalue) AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('returnthis', $DB->get_field_sql($sql, array('paramvalue' => 'returnthis')));
+
+        // Testing all null ocurrences, return null
+        // Note: under mssql, if all elements are nulls, at least one must be a "typed" null, hence
+        // we cannot test this in a cross-db way easily, so next 2 tests are using
+        // different queries depending of the DB family
+        $customnull = $DB->get_dbfamily() == 'mssql' ? 'CAST(null AS varchar)' : 'null';
+        $sql = "SELECT COALESCE(null, null, " . $customnull . ") AS test" . $DB->sql_null_from_clause();
+        $this->assertNull($DB->get_field_sql($sql, array()));
+        $sql = "SELECT COALESCE(null, :paramvalue, " . $customnull . ") AS test" . $DB->sql_null_from_clause();
+        $this->assertNull($DB->get_field_sql($sql, array('paramvalue' => null)));
+
+        // Check there are not problems with whitespace strings
+        $sql = "SELECT COALESCE(null, '', null) AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('', $DB->get_field_sql($sql, array()));
+        $sql = "SELECT COALESCE(null, :paramvalue, null) AS test" . $DB->sql_null_from_clause();
+        $this->assertEqual('', $DB->get_field_sql($sql, array('paramvalue' => '')));
+    }
+
     function test_sql_concat() {
         $DB = $this->tdb;
         $dbman = $DB->get_manager();