SUMIF to SQL SUM and CASE

Same split as COUNTIF: one total → WHERE. Several totals across columns → CASE.

SELECT SUM(total_amount) FROM Orders WHERE status = 'Shipped';

SELECT SUM(CASE WHEN status = 'Shipped' THEN total_amount ELSE 0 END) AS shipped_sales
FROM Orders;

ELSE 0 keeps the SUM from going NULL when nothing matches.

Canonical translation

SELECT SUM(total_amount) FROM Orders WHERE status = 'Shipped';

SELECT SUM(CASE WHEN status = 'Shipped' THEN total_amount ELSE 0 END) AS shipped_sales
FROM Orders;