Karina Data Scientist

Variables in SQL - complete game changer

If you're copy-pasting the same query 4 times just to change one value, it works... but there's a better way.

Let me show you.

SELECT * FROM Orders WHERE Region = 'West';
SELECT * FROM Orders WHERE Region = 'East';
SELECT * FROM Orders WHERE Region = 'South';
SELECT * FROM Orders WHERE Region = 'Central';

Copy. Paste. Change value. Repeat.
It works. But it's painful.

The better way: Use a variable

Change the region? Change one line. Done.

Why this matters:
- No more find-and-replace across 50 lines
- Change values in one place
- Easier to test different scenarios
- Cleaner stored procedures
- Reusable scripts

SQL Server:
DECLARE @Region VARCHAR(50) = 'West';

PostgreSQL:
DO $$
DECLARE Region VARCHAR(50) := 'West';
BEGIN
-- your query
END $$;

MySQL:
SET @Region = 'West';

Skip the Carousel

1 2

1 day ago | [YT] | 19