prepare() public method
Prepares the SQL statement to be executed. For complex SQL statement that is to be executed multiple times, this may improve performance. For SQL statement with binding parameters, this method is invoked automatically.
public void prepare ( $forRead = null )$forRead boolean
Whether this method is called for a read query. If null, it means the SQL statement should be used to determine whether it is for read or write. throws yii\db\Exception
if there is any DB err