null值與任意值比較時都為fasle

not in 、"!="、"not like"條件過濾都會過濾掉null值的數據

SELECT * from temp;

SELECT * from temp where score not in (70);

?

?返回null解決方法:

SELECT * from temp where score not in (70) or score is null;SELECT * from temp where score IFNULL(score,'') != 70;