Where to look for an SQL string?

[eluser]Bikun[/eluser]
How could I get to know in which file and line is error occurred?

Error is as follows, but it's REALLY difficult to figure out the exact file where I should make changes:

Code:

A Database Error Occurred

Error Number: 1054

Unknown column 'is_author' in 'where clause'

SELECT FORMAT(AVG(price), 0) AS average_price FROM (users) WHERE `is_client` = 1