php 带有 Or 条件的 Mysql 案例
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Mysql Case with Or condition
提问by user1187
How to write a case in mysql query which checks for null or 0 for a particular column
如何在 mysql 查询中编写一个案例来检查特定列的 null 或 0
CREATE TABLE tblConfirmationStatus (Confirm_Status TINY INT)
INSERT INTO tblConfirmationStatus
Confirm_Status
VALUES
(1),
(0),
(1),
({null}),
(0),
(1),
({null})
Required Output
所需输出
ConfirmStatus
确认状态
Confirmed Not Confirmed Confirmed Not Confirmed Not Confirmed Confirmed Not Confirmed
0 or Null - Not Confirmed, 1-Confirmed
0 或 Null - 未确认，1 - 已确认
SELECT CASE Confirm_Status
WHEN NULL OR 0 THEN 'Not Confirmed'
ELSE 'Confirmed' END AS ConfirmStatus
FROM tblConfirmationStatus;
回答by OMG Ponies
There's two options for CASE statements - the one you posted, or:
CASE 语句有两种选择 - 您发布的一种，或者：
SELECT CASE
WHEN Confirm_Status IS NULL OR Confirm_Status = 0 THEN 'Not Confirmed'
ELSE 'Confirmed'
END AS ConfirmStatus
But you could probably use:
但你可能会使用：
SELECT CASE
WHEN Confirm_Status > 0 THEN 'Confirmed'
ELSE 'Not Confirmed'
END AS ConfirmStatus
NULLis the absence of a value, so checking for values above zero should fall into the same category as zero.
NULL是缺少值，因此检查大于零的值应该与零属于同一类别。
回答by Omesh
SELECT IF((Confirm_Status IS NULL OR Confirm_Status = 0),
'Not Confirmed', 'Confirmed') AS ConfirmStatus
FROM tblConfirmationStatus;
回答by Adriaan Stander
Have you had a look at using IFNULLoperator.
您是否看过使用IFNULL运算符。
IFNULL(expr1,expr2)
If expr1 is not NULL, IFNULL() returns expr1; otherwise it returns expr2. IFNULL() returns a numeric or string value, depending on the context in which it is used.
IFNULL(expr1,expr2)
如果 expr1 不为 NULL，则 IFNULL() 返回 expr1；否则返回 expr2。IFNULL() 返回数字或字符串值，具体取决于使用它的上下文。
