Categories:

Period functions

PERIOD_PRECEDES

Returns TRUE if the first PERIOD ends at or before the second PERIOD begins.

See also:

PERIOD data type , Period functions

Syntax

PERIOD_PRECEDES( <period1>, <period2> )

Arguments

period1

The first PERIOD value.

period2

The second PERIOD value. Must have the same element type as period1.

Returns

BOOLEAN.

Usage notes

  • TRUE when PERIOD_END(period1) <= PERIOD_BEGIN(period2).
  • Adjacent periods that meet also precede: PERIOD_PRECEDES([a, b), [b, c)) is TRUE.

Examples

This example shows a period that precedes another (it ends at or before the second begins), and one that doesn’t:

WITH periods AS (
  SELECT
    PERIOD(DATE) '[2024-01-01, 2024-04-01)' AS p_left,
    PERIOD(DATE) '[2024-04-01, 2024-07-01)' AS p_right,
    PERIOD(DATE) '[2024-01-01, 2024-07-01)' AS p_long
)
SELECT
    PERIOD_PRECEDES(p_left, p_right) AS precedes_true,
    PERIOD_PRECEDES(p_long, p_right) AS precedes_false
  FROM periods;

+---------------+----------------+
| PRECEDES_TRUE | PRECEDES_FALSE |
|---------------+----------------|
| True          | False          |
+---------------+----------------+