framework/db/SchemaBuilderTrait.php
public function json()
    {
        /*
         * TODO Remove in Yii 2.1
         *
         * Disabled due to bug in MySQL extension
         * @link https://bugs.php.net/bug.php?id=70384
         */
        if (version_compare(PHP_VERSION, '5.6', '<') && $this->getDb()->getDriverName() === 'mysql') {
            throw new \yii\base\Exception('JSON column type is not supported in PHP < 5.6');
        }

        return $this->getDb()->getSchema()->createColumnSchemaBuilder(Schema::TYPE_JSON);
    }
public function json()
    {
        /*
         * TODO Remove in Yii 2.1
         *
         * Disabled due to bug in MySQL extension
         * @link https://bugs.php.net/bug.php?id=70384
         */
        if (version_compare(PHP_VERSION, '5.6', '<') && $this->getDb()->getDriverName() === 'mysql') {
            throw new \yii\base\Exception('JSON column type is not supported in PHP < 5.6');
        }

        return $this->getDb()->getSchema()->createColumnSchemaBuilder(Schema::TYPE_JSON);
    }
Creates a JSON column.
@return ColumnSchemaBuilder the column instance which can be further customized.
@since 2.0.14
@throws \yii\base\Exception