Question

I am writing a pgplsql function in which I have a variable var that could be NULL or valorized. In a later query I do:

SELECT * FROM table WHERE column = var

that, in case of a NULL var, becomes

SELECT * FROM table WHERE column = NULL

So the query fails with NULL, because, as PostgreSQL documentation says,

The null value represents an unknown value, and it is not known whether two unknown values are equal

I resolved it with a CASE statement:

SELECT * FROM table WHERE 
( CASE WHEN var IS NULL THEN column IS NULL ELSE column = var END ) = TRUE

But I am unsure wether this is the best way to resolve the question… do you have any good alternative?

Answer 1

SELECT * FROM table WHERE column IS NOT DISTINCT FROM var