NULLIF関数を試してください:
SELECT LEAST(
nullif( number1, 0 ),
nullif( number2, 0 ),
nullif( number3, 0 ),
nullif( number4, 0 ))
FROM numbers
デモ->
NULLIF関数を試してください:
SELECT LEAST(
nullif( number1, 0 ),
nullif( number2, 0 ),
nullif( number3, 0 ),
nullif( number4, 0 ))
FROM numbers
デモ->