Re: SQL Error (1241): Operand should contain 1 column(s)

[Abhishek Gupta]

Hi Peter,

As I was working more in this direction, I found where the mistake was. Sorry not hit my mind at first place but will also make you understand why I am asking about debugging and useful tools of any sort.

The problem was that a trigger is associated with the table.

============================================================================================================================================================

create trigger tr_ftr_ins_NMId_FTRIdentifier
before insert
on t_ftr for each row
begin
SET @minftrid = (select min(itf.FTRId) as minftrid, itf.NMId, itf.FTRIdentifier from T_FTR itf where itf.NMId = new.NMId and itf.FTRIdentifier = new.FTRIdentifier group by itf.NMId, itf.FTRIdentifier having count(1) > 1);
update t_ftr tf SET tf.FTRIdentifier = NULL where tf.NMId = new.NMId and tf.FTRIdentifier = new.FTRIdentifier and tf.FTRId > @minftrid;
end$$

============================================================================================================================================================

SET @minftrid = <Returning multiple columns from select>

============================================================================================================================================================


But I believe this is just accidental. Hence will appreciate if you can answer below question

============================================================================================================================================================

Q1. Are there any open source/freeware tools that can help me diagnose this or similar kind of problem/s, like what part of SQL query is leading to that error, stored procedure debugging tool etc.

Q2. With that said, I will appreciate if you can mention or point me to a link, that list general and useful tools/utilities a MySQL DBA and Developer should know about.

Thanks|Regards
Abhishek G