Question

Imagine you have a User table with FirstName, MiddleName, LastName.
For the sake of this sample only FirstName is mandatory.

在NOT失去价值时,最快的办法是将这些3个领域集中起来,并将其与“、”分开,这样:

If only FirstName is NOT null, we should get "John" as result.
If only FirstName and LastName are not null, we should have "John,Wayne" as result.
If FirstName, MiddleName and LastName are not null, we should have "John,M,Wayne" as result.

先进。

Answer 1

或许可以这样说:

FirstName +(CASE WHEN MiddleName IS NULL THEN    ELSE  , +MiddleName END)
+(CASE WHEN LastName IS NULL THEN    ELSE  , +LastName END)

Answer 2

2种不同的方法

--syntax
select Firstname + isnull( ,  +Middlename,   ) + coalesce( ,  +LastName,   )
from 
--testdata
(select  John  firstname,  W  middlename,  Wayne  lastname
union all select  John  firstname, null middlename,  Wayne  lastname
union all select  John  firstname,  W  middlename, null lastname) a

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