allow insert..select (insertUsing()) to have empty $columns (#46605)

Enables queries which insert *all* columns from the source table into the destination table, e.g. "insert into users select * from users”, when the table schemas exactly match.

alter testPreservedAreAppliedByInsertUsing() to not conflict with new behaviour

src/Illuminate/Database/Query/Grammars/Grammar.php

@@ -1062,7 +1062,13 @@ public function compileInsertGetId(Builder $query, $values, $sequence)
      */
     public function compileInsertUsing(Builder $query, array $columns, string $sql)
     {
-        return "insert into {$this->wrapTable($query->from)} ({$this->columnize($columns)}) $sql";
+        $table = $this->wrapTable($query->from);
+
+        if (empty($columns)) {
+            return "insert into {$table} $sql";
+        }
+
+        return "insert into {$table} ({$this->columnize($columns)}) $sql";
     }
 
     /**

tests/Database/DatabaseQueryBuilderTest.php

@@ -2794,6 +2794,21 @@ function (Builder $query) {
         $this->assertEquals(1, $result);
     }
 
+    public function testInsertUsingWithEmptyColumns()
+    {
+        $builder = $this->getBuilder();
+        $builder->getConnection()->shouldReceive('affectingStatement')->once()->with('insert into "table1" select * from "table2" where "foreign_id" = ?', [5])->andReturn(1);
+
+        $result = $builder->from('table1')->insertUsing(
+            [],
+            function (Builder $query) {
+                $query->from('table2')->where('foreign_id', '=', 5);
+            }
+        );
+
+        $this->assertEquals(1, $result);
+    }
+
     public function testInsertUsingInvalidSubquery()
     {
         $this->expectException(InvalidArgumentException::class);
@@ -3351,11 +3366,11 @@ public function testPreservedAreAppliedByInsertGetId()
     public function testPreservedAreAppliedByInsertUsing()
     {
         $builder = $this->getBuilder();
-        $builder->getConnection()->shouldReceive('affectingStatement')->once()->with('insert into "users" () select *', []);
+        $builder->getConnection()->shouldReceive('affectingStatement')->once()->with('insert into "users" ("email") select *', []);
         $builder->beforeQuery(function ($builder) {
             $builder->from('users');
         });
-        $builder->insertUsing([], $this->getBuilder());
+        $builder->insertUsing(['email'], $this->getBuilder());
     }
 
     public function testPreservedAreAppliedByUpsert()