Mysql In子句中选择所有记录

Question

I have a store procedure like this:

select * from A where A.column1 IN (parameter) AND A.column2 IN (parameter2)

So, I need to know if there is any way to select all records in the column1 when 'parameter' is empty (the same for column2 with parameter2)

Thanks for the help!

Answer 1

select * from A 
where (parameter is null or A.column1 IN (parameter))
  and (parameter2 is null or A.column2 IN (parameter2))