//create a trigger
Delimiter $$
Create the trigger testa before insert
On the professional information table for each row
The begin
If demand number & gt;=new. Has hired number then
Number=new. Set has hired already hired number
Update whether to hire the set='successfully employing the from professional information table join z right candidate information table q
Professional requirements on z.=q. Professional limit has hired number;
The else
Declare the error condition for 'beyond the limit;
end if;
End
$$
ERROR 1193: (HY000) Unknown system variable 'has hired number'
In the applicant information in the table has already hired number field name how to solve this problem, and limit variables can be used