what does this mean
:=
in sql ?
if found some sql using like that symbol example
select col1, col2, @pv:=col3 as 'col3' from table1
join
(select @pv:=1)tmp
where col1=@pv
Thank you in advance.
using this: here variable are prepended with an @ sign to suggest user-defined variable.
A variable, without @, is a system variable, which you cannot define yourself.
SET @pv:=1// we set a variable
i.e :=
is used as assignment operator like normal =
else where.
see here:http://dev.mysql.com/doc/refman/5.0/en/user-variables.html
and also see a good post here:MySQL: @variable vs. variable. Whats the difference?