Double colon (::) notation in SQL

Question

Have picked up someone\'s code and this is a part of a where clause, anyone know what the double colon indicates?

b.date_completed >  a.dc::date + INTERVA         


        

Answer 1

It is a CAST operation(cast to a date type).

Example:

SELECT now()::timestamp(0);

Is equivalent to:

SELECT 
    CAST (now() AS timestamp(0));

They both result in casting now() to timestamp in the following format: YYYY-MM-DD HH:MM:SS