yii\db\mysql\QueryBuilder::insert PHP Method

    public function insert($table, $columns, &$params)
    {
        $schema = $this->db->getSchema();
        if (($tableSchema = $schema->getTableSchema($table)) !== null) {
            $columnSchemas = $tableSchema->columns;
        } else {
            $columnSchemas = [];
        }
        $names = [];
        $placeholders = [];
        foreach ($columns as $name => $value) {
            $names[] = $schema->quoteColumnName($name);
            if ($value instanceof Expression) {
                $placeholders[] = $value->expression;
                foreach ($value->params as $n => $v) {
                    $params[$n] = $v;
                }
            } else {
                $phName = self::PARAM_PREFIX . count($params);
                $placeholders[] = $phName;
                $params[$phName] = !is_array($value) && isset($columnSchemas[$name]) ? $columnSchemas[$name]->dbTypecast($value) : $value;
            }
        }
        if (empty($names) && $tableSchema !== null) {
            $columns = !empty($tableSchema->primaryKey) ? $tableSchema->primaryKey : [reset($tableSchema->columns)->name];
            foreach ($columns as $name) {
                $names[] = $schema->quoteColumnName($name);
                $placeholders[] = 'DEFAULT';
            }
        }
        return 'INSERT INTO ' . $schema->quoteTableName($table) . (!empty($names) ? ' (' . implode(', ', $names) . ')' : '') . (!empty($placeholders) ? ' VALUES (' . implode(', ', $placeholders) . ')' : ' DEFAULT VALUES');
    }