What does ":1", ":2" in SQL mean?

Question

I am looking at a sql statement that looks like this:

...
AND col2_.col_date >= :1
AND col2_.col_date <= :2
...

and I have no idea what :1 and :2 does??

Can someone enlighten me,

Thanks, :)

Answer 1

They're placeholders in a parametrized query, waiting for the program to come along and supply the parameters.