A PostgreSQL function or a stored procedure is a set of SQL and procedural commands such as declarations, assignments, loops, flow-of-control etc. stored on the database server and can be involved using the SQL interface. And it is also known as PostgreSQL stored procedures.

How do I run a function in PostgreSQL?

The use of assignments and SELECT statements to execute functions is standard in PL/pgSQL because all functions in a PostgreSQL database must return a value of some type. Use the PERFORM keyword to call a function and ignore its return data. Example 11-50 shows the syntax of the PERFORM keyword.

What does PostgreSQL count function do?

The COUNT(*) function returns the number of rows returned by a SELECT statement, including NULL and duplicates. When you apply the COUNT(*) function to the entire table, PostgreSQL has to scan the whole table sequentially. … This is related to the PostgreSQL MVCC implementation.