20 Oct 2022 Dominika Florczykowska What Does a Double Colon Operator in PostgreSQL Do? The double colon operator :: in PostgreSQL is a synonym for CAST, which converts a value into a different data type. If you are curious about the details , read on! Have you ever seen a double colon (::) operator in someone’s PostgreSQL code? It would look something like this: SELECT '2022-09-02'::date; This code converts the text '2022-09-02' to a date datatype. As mentioned above, the double colon replaces the CAST operator. Read more