From 3a55ee2f5e08dda91ae37ac72769abd629ae80a1 Mon Sep 17 00:00:00 2001
From: Eloy Lafuente <stronk7@moodle.org>
Date: Wed, 17 Nov 2010 10:39:56 +0000
Subject: [PATCH] MDL-25268 dml - improved limitnum/limitfrom regexp in ms
 drivers + tests

---
 lib/dml/mssql_native_moodle_database.php  |  4 ++--
 lib/dml/simpletest/testdml.php            | 19 +++++++++++++++++++
 lib/dml/sqlsrv_native_moodle_database.php |  4 ++--
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/lib/dml/mssql_native_moodle_database.php b/lib/dml/mssql_native_moodle_database.php
index d8123119631..884b3682317 100644
--- a/lib/dml/mssql_native_moodle_database.php
+++ b/lib/dml/mssql_native_moodle_database.php
@@ -686,8 +686,8 @@ class mssql_native_moodle_database extends moodle_database {
         if ($limitfrom or $limitnum) {
             if ($limitnum >= 1) { // Only apply TOP clause if we have any limitnum (limitfrom offset is handled later)
                 $fetch = $limitfrom + $limitnum;
-                $sql = preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',
-                                    "\\1SELECT\\2 TOP $fetch", $sql);
+                $sql = preg_replace('/^([\s(])*SELECT([\s]+)(DISTINCT|ALL)?(?!\s*TOP\s*\()/i',
+                                    "\\1SELECT\\2\\3 TOP $fetch", $sql);
             }
         }
 
diff --git a/lib/dml/simpletest/testdml.php b/lib/dml/simpletest/testdml.php
index 7514938da78..259f81a8354 100755
--- a/lib/dml/simpletest/testdml.php
+++ b/lib/dml/simpletest/testdml.php
@@ -3047,6 +3047,25 @@ class dml_test extends UnitTestCase {
         $DB->insert_record($tablename, array('course' => 5, 'content' => 'hello', 'name'=>'def'));
         $DB->insert_record($tablename, array('course' => 2, 'content' => 'universe', 'name'=>'abc'));
 
+        // test limits in queries with DISTINCT/ALL clauses and multiple whitespace. MDL-25268
+        $sql = "SELECT   DISTINCT   course
+                  FROM {{$tablename}}
+                 ORDER BY course";
+        // only limitfrom
+        $records = $DB->get_records_sql($sql, null, 1);
+        $this->assertEqual(2, count($records));
+        $this->assertEqual(3, reset($records)->course);
+        $this->assertEqual(5, next($records)->course);
+        // only limitnum
+        $records = $DB->get_records_sql($sql, null, 0, 2);
+        $this->assertEqual(2, count($records));
+        $this->assertEqual(2, reset($records)->course);
+        $this->assertEqual(3, next($records)->course);
+        // both limitfrom and limitnum
+        $records = $DB->get_records_sql($sql, null, 2, 2);
+        $this->assertEqual(1, count($records));
+        $this->assertEqual(5, reset($records)->course);
+
         // we have sql like this in moodle, this syntax breaks on older versions of sqlite for example..
         $sql = "SELECT a.id AS id, a.course AS course
                   FROM {{$tablename}} a
diff --git a/lib/dml/sqlsrv_native_moodle_database.php b/lib/dml/sqlsrv_native_moodle_database.php
index 60a2d1753e4..673bc0dcea6 100644
--- a/lib/dml/sqlsrv_native_moodle_database.php
+++ b/lib/dml/sqlsrv_native_moodle_database.php
@@ -778,8 +778,8 @@ class sqlsrv_native_moodle_database extends moodle_database {
         $offset = max(0, $offset);
 
         if ($limit > 0 && $offset == 0) {
-            $sql1 = preg_replace('/^([\s(])*SELECT( DISTINCT | ALL)?(?!\s*TOP\s*\()/i',
-                "\\1SELECT\\2 TOP $limit", $sql);
+            $sql1 = preg_replace('/^([\s(])*SELECT([\s]+)(DISTINCT|ALL)?(?!\s*TOP\s*\()/i',
+                                 "\\1SELECT\\2\\3 TOP $limit", $sql);
         } else {
             // Only apply TOP clause if we have any limitnum (limitfrom offset is handled later)
             if ($limit < 1) {