MySQL 程序式写法
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2022-05-19 17:35:40
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1. IF
if (condition, result1, result2)
IF(expr1 is not null, expr1, expr2) 等价于 ifnull(expr1, expr2)
ifnull()效率胜过if()
2. Case
case
when day(MaxDate)<=10 then 1
when day(MaxDate)<=20 then 2
else 3
end
if (condition, result1, result2)
IF(expr1 is not null, expr1, expr2) 等价于 ifnull(expr1, expr2)
ifnull()效率胜过if()
2. Case
case
when day(MaxDate)<=10 then 1
when day(MaxDate)<=20 then 2
else 3
end
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