MySQL排序规则错误

Question

I have the following query. It works fine if I execute it in MySQL. But when I call it from my PHP program it give me this error:

[PDOException]

SQLSTATE[HY000]: General error: 1267 Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_unicode_ci,COERCIBLE) for operation '='

This is the query:

   SELECT * FROM  tab
    WHERE Time >= UTC_TIME
    AND Time < TIME( DATE_SUB( UTC_TIMESTAMP() , INTERVAL -5 MINUTE )) 
        AND Enabled =1
    AND (
     LastTimeStamp IS NULL 
     OR DATE( LastTimeStamp ) != DATE(UTC_TIMESTAMP())
        )
    AND d = ( 
        SELECT d
        FROM  days
        WHERE DayName = ( 
        SELECT DAYNAME(UTC_TIMESTAMP())) 
         )

Also both the tab and the days have latin1_sweedish_ci collation.

Can some one help me? I am using Laravel framework for my application.