Is there a PostgreSQL equivalent of SQLite's IS operator?

Question

In SQLite , IS is a binary operator that behaves exactly like = except when one or both of the operands are NULL . In the case where both operands are NULL , the IS operator evaluates to TRUE . In the case where one operand is NULL , but not the other, the IS operand evaluates to FALSE .

I was looking for a similar operator in PostgreSQL, but I could not find one. Is there an equivalent of SQLite's IS operator in PostgreSQL? If not, what is the best/least-complicated work-around?

To clarify, SELECT column1 IS column2 ... is allowed in SQLite, but PostgreSQL raises a syntax error.

Answer 1

尝试使用IS（NOT）DISTINCT FROM运算符。

Answer 2

Apparently it's possible in postgresql (see dan04's). The query below would work in SQL Server and other DBMSs where that syntax isn't available.

You can simulate by doing:

WHERE (column1 is NULL and column2 is NULL) 
      OR column1 = column2

Answer 3

To add to @Derek's answer:

In MySQL you can use the <=> operator to the same effect:

SELECT * FROM table1 WHERE column1 <=> column2