COALESCE() for blank (but not null) fields

会有一股神秘感。 提交于 2019-11-30 17:17:48
SELECT IFNULL(NULLIF(Field1,''),Field2)

NULLIF returns a NULL if Field1 is blank, while IFNULL returns Field1 if it's not blank or NULL and Field2 otherwise.

You can use a CASE expression:

CASE WHEN Field1 <> '' THEN Field1 ELSE Field2 END

I know I'm late to the party here, but there is a way to do this while still using COALESCE(). This would then work if your value was NULL or ''.

Select COALESCE(NULLIF(Field1,''), Field2)
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