Learning PostgreSQL 11 - Third Edition

Comparison operators

Comparison operators are less (<), more (>), less or equal ( <=), more or equal (>=), equal (=), and not equal (<> or !=—these two are synonyms). These operators can compare not only numbers but any values that can be compared, for example, dates or strings. There is a BETWEEN construct that also relates to comparing. Consider the following:

x BETWEEN a AND b

The preceding code is equivalent to the following:

x >= a AND x <= b

The OVERLAPS operator checks to see whether two ranges of dates overlap. Here is an example:

car_portal=> SELECT 1 WHERE (date '2018-10-15', date '2018-10-31')   OVERLAPS (date '2018-10-25', date '2018-11-15'); ?column?----------        1

Formally, comparison operators have different precedence: >= and ...