fix: Support DISTINCT in GROUP_CONCAT

Author: Javakky-pxv

src/Parser/ExpressionParser.php

@@ -137,10 +137,14 @@ private function getListExpression(array $tokens)
         $needs_comma = false;
         $args = [];
 
+        if (isset($tokens[0]) && $tokens[0]->value == "DISTINCT") {
+            $distinct = true;
+            $pos++;
+        }
+
         while ($pos < $token_count) {
             $arg = $tokens[$pos];
 
-
             if ($arg->value === ',') {
                 if ($needs_comma) {
                     $needs_comma = false;
@@ -151,14 +155,21 @@ private function getListExpression(array $tokens)
                 }
             }
 
+
+            if ($arg->value === 'ORDER') {
+                $p = new OrderByParser($pos, $tokens);
+                [$pos, $order_by] = $p->parse();
+                continue;
+            }
+
             $p = new ExpressionParser($tokens, $pos - 1);
             list($pos, $expr) = $p->buildWithPointer();
             $args[] = $expr;
             $pos++;
             $needs_comma = true;
         }
 
-        return [$distinct, $args];
+        return [$distinct, $args, $order_by ?? null];
     }
 
     /**

src/Processor/Expression/FunctionEvaluator.php

@@ -67,7 +67,7 @@ public static function evaluate(
             case 'CONCAT':
                 return self::sqlConcat($conn, $scope, $expr, $row, $result);
             case 'GROUP_CONCAT':
-                return self::sqlGroupConcat($conn, $scope, $expr, $row, $result);
+                return self::sqlGroupConcat($conn, $scope, $expr, $result);
             case 'FIELD':
                 return self::sqlColumn($conn, $scope, $expr, $row, $result);
             case 'BINARY':
@@ -941,18 +941,23 @@ private static function sqlGroupConcat(
         FakePdoInterface $conn,
         Scope $scope,
         FunctionExpression $expr,
-        array $row,
         QueryResult $result
     ): string {
         $args = $expr->args;
 
-        $final_concat = "";
-        foreach ($args as $arg) {
-            $val = (string) Evaluator::evaluate($conn, $scope, $arg, $row, $result);
-            $final_concat .= $val;
+        $items = [];
+        foreach ($result->rows as $row) {
+            $tmp_str = "";
+            foreach ($args as $arg) {
+                $val = (string) Evaluator::evaluate($conn, $scope, $arg, $row, $result);
+                $tmp_str .= $val;
+            }
+            if ($tmp_str !== "" && (!$expr->distinct || !isset($items[$tmp_str]))) {
+                $items[$tmp_str] = $tmp_str;
+            }
         }
 
-        return $final_concat;
+        return implode(",", array_values($items));
     }
 
     /**

tests/EndToEndTest.php

@@ -1,4 +1,5 @@
 <?php
+
 namespace Vimeo\MysqlEngine\Tests;
 
 use PDOException;
@@ -911,6 +912,33 @@ public function testInsertWithNullAndEmpty()
         );
     }
 
+    public function testGroupConcat()
+    {
+        $pdo = self::getConnectionToFullDB(false);
+
+        $query = $pdo->prepare(
+            'SELECT `type`, GROUP_CONCAT(DISTINCT `profession`) as `profession_list`
+            FROM `video_game_characters`
+            GROUP BY `type`'
+        );
+
+        $query->execute();
+
+        $this->assertSame(
+            [
+                [
+                    "type" => "hero",
+                    "profession_list" => "plumber,hedgehog,earthworm,monkey,pokemon,princess,boxer,yellow circle,dinosaur,not sure,sure"
+                ],
+                [
+                    "type" => "villain",
+                    "profession_list" => "evil dinosaur,evil doctor,throwing shit from clouds,evil chain dude"
+                ],
+            ],
+            $query->fetchAll(\PDO::FETCH_ASSOC)
+        );
+    }
+
     public function testOrderBySecondDimensionAliased()
     {
         $pdo = self::getConnectionToFullDB(false);