在MySQL中,IF-THEN-ELSE语句用于根据条件分别执行分支的代码。
MySQL中IF-THEN-ELSE语句的语法为:
IF condition1
THEN
{...statements
to
execute
when
condition1
is
TRUE
...}
[ ELSEIF condition2
FALSE
and
condition2
...} ]
[
ELSE
both condition1
condition2 are
END
IF;
DELIMITER //
CREATE
FUNCTION
IncomeLevel ( monthly_value
INT
)
RETURNS
varchar
(20)
BEGIN
DECLARE
income_level
(20);
IF monthly_value <= 4000
SET
income_level =
'低收入'
;
ELSEIF monthly_value > 4000
AND
monthly_value <= 7000
'中等收入'
'高收入'
RETURN
income_level;
; //
DELIMITER ;
SELECT
UnitPrice
as
'单价'
,
IF (UnitPrice < 10 ,
'9.9专区'
IF(UnitPrice >=10
UnitPrice <20 ,
'19.9专区'
'热销'
AS
'分类'
FROM
orderdetails
语法:
IF(条件,条件满足时的值,条件不满足时的值)
比如
IF(state=1,
'状态正常'
'状态异常'
如果state字段的值等于1,则状态正常。
原文链接:https://codingdict.com/