CDbCommand - Three Tables Join and IN Clause Syntax - mysql

Question

In my Yii application, I have following database structure:
Table user (id, firstName, lastName)
Table category (id, categoryName)
Table item (id, categoryId, name)
Table usergroup(id, userId, groupName)
I am trying to run following query:
$sql = 'SELECT a.id, a.firstName, a.lastName, b.id, b.categoryName, c.id, c.name
FROM user AS a
INNER JOIN (category AS b ON a.id = b.userId
WHERE b.userId IN (SELECT f.id FROM usergroup f WHERE f.userId=:currentUserId))
INNER JOIN item AS c ON b.id = c.categoryId
WHERE c.name LIKE :listedName';
$command=$connection->createCommand($sql);
$currentUserId = Yii::app()->user->id;
//binding :currentUserId
$command->bindParam(":currentUserId", $currentUserId,PDO::PARAM_STR);
$listedItemName = $data->name;
//binding :listedItemName
$command->bindParam(":listedName", $listedName,PDO::PARAM_STR);
$dataReader=$command->query();
However, I get following excption:
CDbException
CDbCommand failed to execute the SQL statement: SQLSTATE[42000]:
Syntax error or access violation: 1064 You have an error in your SQL
syntax; check the manual that corresponds to your MySQL server version
for the right syntax to use near 'ON a.id = b.userId WHERE b.userId IN
(SELECT f.id FROM usergroup' at line 3.
The SQL statement executed was:
SELECT a.id, a.firstName, a.lastName, b.id, b.categoryName, c.id, c.name FROM user AS a INNER JOIN (category AS b ON a.id = b.userId WHERE b.userId IN (SELECT f.id FROM usergroup f WHERE f.userId=:currentUserId)) INNER JOIN item AS c ON b.id = c.categoryId WHERE c.name LIKE :listedName. Bound with :currentUserId='2', :listedName='Oliver Twist'
Any sort of help or advice will be highly appreciated. Thank You!

Answer 1

You seem to have some parenthesis issue in there as well as possibly an unnecessary sub-select. I am guessing that what you are looking for is:
SELECT a.id, a.firstName, a.lastName, b.id, b.categoryName, c.id, c.name
FROM user AS a
INNER JOIN category AS b ON a.id = b.userId
INNER JOIN usergroup AS f ON f.userID = a.id
INNER JOIN item AS c ON b.id = c.categoryId
WHERE c.name LIKE :listedName'
AND f.userID=:currentUserId;
But, I am unclear on the join between item and category tables. You don't seem to to have foreign for category in items table and are just joining the item id and category id.
I am also unclear on your join between the user table and category table where you are saying the user id = category id. I don't see how these are related.

Answer 2

For update/reference of any one else facing same issue. I later figured out the problem that SQL WHERE CLAUSE should only be used at the end of statement, and I changed the first WHERE clause with AND condition. Here is the working query:
$sql = 'SELECT a.id, a.firstName, a.lastName, b.id, b.categoryName, c.id, c.name
FROM user AS a
INNER JOIN (category AS b ON a.id = b.userId
AND b.userId IN (SELECT f.id FROM usergroup f WHERE f.userId=:currentUserId))
INNER JOIN item AS c ON b.id = c.categoryId
WHERE c.name LIKE :listedName';