Mssql: Support LIMIT and OFFSET

src/QueryBuilder.php

@@ -3,6 +3,7 @@
 namespace ipl\Sql;
 
 use InvalidArgumentException;
+use ipl\Sql\Adapter\Mssql;
 use ipl\Sql\Contract\Adapter;
 
 use function ipl\Stdlib\get_php_type;
@@ -106,6 +107,16 @@ public function assembleInsert(Insert $insert)
      */
     public function assembleSelect(Select $select, array &$values = [])
     {
+        $select = clone $select;
+
+        if (
+            $this->adapter instanceof Mssql
+            && ($select->hasLimit() || $select->hasOffset())
+            && ! $select->hasOrderBy()
+        ) {
+            $select->orderBy(1);
+        }
+
         $sql = array_filter([
             $this->buildWith($select->getWith(), $values),
             $this->buildSelect($select->getColumns(), $select->getDistinct(), $values),
@@ -622,12 +633,24 @@ public function buildLimitOffset($limit = null, $offset = null)
     {
         $sql = [];
 
-        if ($limit !== null) {
-            $sql[] = "LIMIT $limit";
-        }
+        if ($this->adapter instanceof Mssql) {
+            if ($offset !== null || $limit !== null) {
+                // If offset is null, sprintf will convert it to 0
+                $sql[] = sprintf('OFFSET %d ROWS', $offset);
+            }
 
-        if ($offset !== null) {
-            $sql[] = "OFFSET $offset";
+            if ($limit !== null) {
+                // FETCH FIRST n ROWS ONLY for OFFSET 0 would be an alternative here
+                $sql[] = "FETCH NEXT $limit ROWS ONLY";
+            }
+        } else {
+            if ($limit !== null) {
+                $sql[] = "LIMIT $limit";
+            }
+
+            if ($offset !== null) {
+                $sql[] = "OFFSET $offset";
+            }
         }
 
         return implode($this->separator, $sql);

tests/Mssql/SelectTest.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace ipl\Tests\Sql\Mssql;
+
+use ipl\Sql\Adapter\Mssql;
+use ipl\Sql\QueryBuilder;
+use ipl\Sql\Select;
+
+class SelectTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * The SELECT query to test
+     *
+     * @var Select
+     */
+    protected $query;
+
+    /**
+     * The SQL query builder
+     *
+     * @var QueryBuilder
+     */
+    protected $queryBuilder;
+
+    public function setUp()
+    {
+        $this->query = new Select();
+        $this->queryBuilder = new QueryBuilder(new Mssql());
+    }
+
+    public function testLimitOffset()
+    {
+        $this->query->columns('a')->from('b')->orderBy('a')->limit(10)->offset(20);
+
+        $this->assertCorrectStatementAndValues('SELECT a FROM b ORDER BY a OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY');
+    }
+
+    public function testLimitWithoutOffset()
+    {
+        $this->query->columns('a')->from('b')->orderBy('a')->limit(10);
+
+        $this->assertCorrectStatementAndValues('SELECT a FROM b ORDER BY a OFFSET 0 ROWS FETCH NEXT 10 ROWS ONLY');
+    }
+
+    public function testOffsetWithoutLimit()
+    {
+        $this->query->columns('a')->from('b')->orderBy('a')->offset(20);
+
+        $this->assertCorrectStatementAndValues('SELECT a FROM b ORDER BY a OFFSET 20 ROWS');
+    }
+
+    public function testAutomaticallyFixesLimitWithoutOrder()
+    {
+        $this->query->columns('a')->from('b')->limit(10)->offset(30);
+
+        $this->assertCorrectStatementAndValues('SELECT a FROM b ORDER BY 1 OFFSET 30 ROWS FETCH NEXT 10 ROWS ONLY');
+    }
+
+    protected function assertCorrectStatementAndValues($statement, array $values = [])
+    {
+        list($actualStatement, $actualValues) = $this->queryBuilder->assembleSelect($this->query);
+
+        $this->assertSame($statement, $actualStatement);
+        $this->assertSame($values, $actualValues);
+    }
+}

tests/SelectTest.php

@@ -469,6 +469,33 @@ public function testOrderByWithSelect()
         $this->assertCorrectStatementAndValues('ORDER BY (SELECT COUNT(*) FROM table2 WHERE active = ?) DESC', [1]);
     }
 
+    public function testLimitOffset()
+    {
+        $this->query = (new Select())->columns(['a'])->from('b')->limit(4)->offset(1);
+        $this->assertCorrectStatementAndValues(
+            'SELECT a FROM b LIMIT 4 OFFSET 1',
+            []
+        );
+    }
+
+    public function testLimitWithoutOffset()
+    {
+        $this->query = (new Select())->columns(['a'])->from('b')->limit(4);
+        $this->assertCorrectStatementAndValues(
+            'SELECT a FROM b LIMIT 4',
+            []
+        );
+    }
+
+    public function testOffsetWithoutLimit()
+    {
+        $this->query = (new Select())->columns(['a'])->from('b')->offset(1);
+        $this->assertCorrectStatementAndValues(
+            'SELECT a FROM b OFFSET 1',
+            []
+        );
+    }
+
     public function testUnion()
     {
         $unionQuery = (new Select())