Consider i have a user
table and I have three columns mobilePhone
, homePhone
and workPhone
...
I have to select homePhone
for every user as first pref
if there is no value
I'll go for mobilePhone
and
if there is no value for it
I ll go for workPhone
....
Any suggestion how it can be done in mysql..
Try using Sql Server COALESCE (Transact-SQL) ,
Returns the first nonnull expression among its arguments.
Same goes for MySql COALESCE(value,...)
Returns the first non-NULL value in the list, or NULL if there are no non-NULL values.
Something like
SELECT COALESCE(homePhone, mobilePhone, workPhone) ContactPhone
FROM Users
You want the Coalesce
function which returns the first non-null value:
Select Coalesce(homephone, mobilephone, workphone) Phone
From `user`
Coalesce does exist in MySQL. It is an ANSI defined function.
SELECT user, homePhone
FROM user
WHERE homePhone != ''
UNION
SELECT user, mobilePhone
FROM user
WHERE homePhone = '' AND mobilePhone != ''
UNION
SELECT user, workPhone
FROM user
WHERE homePhone = '' AND mobilePhone = ''
您可以使用嵌套的IF
语句或CASE
,也可以使用业务逻辑层执行此作业
Another solution is to use the following SQL:
ISNULL(ISNULL(HomePhone,MobilePhone),WorkPhone) AS Phone
Thanks, Nirmal
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