Question

I’ve been struggling with converting the following SQL to CDBCriteria to be used with a CActiveDataProvider:
“SELECT PresetDeviceLink., Device. FROM PresetDeviceLink INNER JOIN Device ON Device.id = PresetDeviceLink.deviceId WHERE Device.roomId = 1″

Table structure is as follows:

mysql> describe PresetDeviceLink;
+----------+---------+------+-----+---------+----------------+
| Field    | Type    | Null | Key | Default | Extra          |
+----------+---------+------+-----+---------+----------------+
| id       | int(11) | NO   | PRI | NULL    | auto_increment |
| presetId | int(11) | NO   |     | NULL    |                |
| deviceId | int(11) | NO   |     | NULL    |                |
| state    | int(11) | NO   |     | 0       |                |
| value    | int(11) | NO   |     | 32      |                |
+----------+---------+------+-----+---------+----------------+

mysql> describe Device;
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| id          | int(11)      | NO   | PRI | NULL    | auto_increment |
| ref         | int(11)      | NO   |     | NULL    |                |
| roomId      | int(11)      | NO   |     | NULL    |                |
| typeId      | int(11)      | NO   |     | NULL    |                |
| paired      | tinyint(1)   | NO   |     | 0       |                |
| name        | varchar(255) | YES  |     | NULL    |                |
| description | text         | YES  |     | NULL    |                |
| dimmerPos   | int(11)      | NO   |     | 0       |                |
+-------------+--------------+------+-----+---------+----------------+

My code in my controller is as follows:

$criteria = new CDbCriteria;
$criteria->select = 'PresetDeviceLink.*, Device.*';
$criteria->join = 'INNER JOIN Device ON Device.id = PresetDeviceLink.deviceId';
$criteria->condition = 'Device.roomId = 1';

$presetDeviceLink=new CActiveDataProvider('PresetDeviceLink', array(
    'criteria' => $criteria,
));

When run I get the following error:

CDbCommand failed to execute the SQL statement: SQLSTATE[42S22]: <b>Column not
found</b>: 1054 Unknown column 'PresetDeviceLink.deviceId' in 'on clause'. The SQL
statement executed was: SELECT COUNT(*) FROM `PresetDeviceLink` `t` INNER JOIN
Device ON Device.id = PresetDeviceLink.deviceId WHERE Device.roomId = 1 

The strange thing is, If I use ‘Device’ as the CActiveDataProvider source and change the join statement to join to ‘PresetDeviceLink’, it then complains that the Device.roomId column could not be found.

Do I just not understand how CActiveDataProvider works? It looks to me that I can only use a condition (in a join or where clause) from a field in the table that I pass to the CActiveDataProvider. Any advice?

PS – the SQL query works beautifully in the MySQL console.

Thanks in advance,
Ben

Answer 1

As is visible in the “The SQL statement executed was:” line, the first table was aliased to t. This is Yii’s standard behaviour.

As a result of this, you should use that alias to refer to that table instead of PresetDeviceLink. Or you could try setting $criteria->alias = 'PresetDeviceLink'; before using it in the CActiveDataProvider, though I have not personally tried that option, it should work.