Operators are similar to functions (see Section
on page ). Table lists
the most common operators.
All data types support the standard comparison operators <,
<=, =, >=, >, and <>.
Not all operator/type combinations are defined, however. For example, if you
try to add two DATE values, you will get an error, as shown in the
first query of Figure .
test=> SELECT CAST('1/1/1992' AS DATE) + CAST('1/1/1993' AS DATE);
ERROR: Unable to identify an operator '+' for types 'date' and 'date'
You will have to retype this query using an explicit cast
test=> SELECT CAST('1/1/1992' AS DATE) + CAST('1 year' AS INTERVAL);
?column?
------------------------
1993-01-01 00:00:00-05
(1 row)
test=> SELECT CAST('1/1/1992' AS TIMESTAMP) + '1 year';
?column?
------------------------
1993-01-01 00:00:00-05
(1 row)