Question

i am trying to execute the records that have TotalTime null value from the table NewTimeAttendance…TotalTime datatype nchar(10)

select * from newtimeattendance where TotalTime =  'NULL'

….nothing

select * from newtimeattendance where TotalTime =  'null'

….nothing

select * from newtimeattendance where TotalTime =  'Null'

….nothing

select * from newtimeattendance where TotalTime =  null

….nothing

select * from newtimeattendance where TotalTime =  Null

….nothing

select * from newtimeattendance where TotalTime =  NULL

….nothing

when i select the whole table i can see that there is some NULL TotalTime values..!!

it is small select statment ..why doesn’t it work ? is there a way (special way ) to execute the ‘NULL’ with nchar type ?!

thanks in advance

Answer 1

You need to use IS NULL

select * from newtimeattendance where TotalTime IS NULL

The MySQL doc has some good information on dealing with NULL values:
http://dev.mysql.com/doc/refman/5.0/en/working-with-null.html