MySQL kehrt 0 zurück, wenn null
SELECT IFNULL(field, 0) AS field FROM products WHERE id = 1
SELECT IFNULL(SUM(field), 0) as field FROM products
Embarrassed Emu
SELECT IFNULL(field, 0) AS field FROM products WHERE id = 1
SELECT IFNULL(SUM(field), 0) as field FROM productsSELECT *
FROM contacts
WHERE last_name IS NULL;##syntax:
SELECT IFNULL(col_with_null_value, default_value);
##you can see the result select with the string NA where the document is null:
SELECT IFNULL(user_document_id, 'NA');SELECT IFNULL(NULL, "W3Schools.com");IFNULL(MAX(EMAIL), "[email protected]") as emailSELECT * from TABLE where CODE IS NULL OR CODE!='C'