#23327 Moving code from the query builder to the eloquent builder (#23357)

A previous pull request #19013, which aimed to solve the issue of multiple select statements causing an SQL error within a withCount function, assumed a sub query would only need one select statement.

This is not the case, so the code that removes excess filters is moved to the withCount method where the sub query does only need one select.

Author: ChrisAtUdemy

src/Illuminate/Database/Eloquent/Concerns/QueriesRelationships.php

@@ -210,14 +210,18 @@ public function withCount($relations)
 
             $query->callScope($constraints);
 
-            $query->mergeConstraintsFrom($relation->getQuery());
+            $query = $query->mergeConstraintsFrom($relation->getQuery())->toBase();
+
+            if (count($query->columns) > 1) {
+                $query->columns = [$query->columns[0]];
+            }
 
             // Finally we will add the proper result column alias to the query and run the subselect
             // statement against the query builder. Then we will return the builder instance back
             // to the developer for further constraint chaining that needs to take place on it.
             $column = $alias ?? Str::snake($name.'_count');
 
-            $this->selectSub($query->toBase(), $column);
+            $this->selectSub($query, $column);
         }
 
         return $this;

src/Illuminate/Database/Query/Builder.php

@@ -279,8 +279,6 @@ public function selectSub($query, $as)
     protected function parseSubSelect($query)
     {
         if ($query instanceof self) {
-            $query->columns = [$query->columns[0]];
-
             return [$query->toSql(), $query->getBindings()];
         } elseif (is_string($query)) {
             return [$query, []];

tests/Database/DatabaseQueryBuilderTest.php

@@ -1449,10 +1449,11 @@ public function testAggregateWithSubSelect()
             return $results;
         });
         $builder->from('users')->selectSub(function ($query) {
-            $query->from('posts')->select('foo')->where('title', 'foo');
+            $query->from('posts')->select('foo', 'bar')->where('title', 'foo');
         }, 'post');
         $count = $builder->count();
         $this->assertEquals(1, $count);
+        $this->assertEquals('(select "foo", "bar" from "posts" where "title" = ?) as "post"', $builder->columns[0]->getValue());
         $this->assertEquals(['foo'], $builder->getBindings());
     }