Case Labels - SQL Programming

A CASE expression returns a different value per row based on conditions. It is the SQL way to label or bucket data.

Program

Play the script to label each task as high, medium, or low priority.

case_labels.sql

CREATE TABLE tasks (name TEXT, priority INTEGER);
INSERT INTO tasks VALUES ('deploy', 5), ('docs', 2), ('cleanup', 0);
SELECT name, priority, CASE WHEN priority >= 3 THEN 'high' WHEN priority >= 1 THEN 'medium' ELSE 'low' END AS label FROM tasks ORDER BY priority DESC;

CASE `CASE WHEN ... THEN ...` returns a value chosen per row.

first match wins Conditions are tested top to bottom; the first matching `WHEN` decides the label.

ELSE `ELSE 'low'` is the default when no `WHEN` matches.