Teradata SQL - First Day of a Month

Introduction

In Teradata, we can derive the first day of the month from a specified date.

Code snippet

The following code snippet shows the month start date of the current month:

SELECT CURRENT_DATE - EXTRACT(DAY FROM CURRENT_DATE) + 1 AS MONTH_START_DATE;

Output:

MONTH_START_DATE

1 1/02/2021

Similarly, table column or DATE expressions can be used with the function.

SELECT DATE'2021-12-31' - EXTRACT(DAY FROM DATE'2021-12-31') + 1 AS MONTH_START_DATE;

Output:

MONTH_START_DATE

1 1/12/2021