MS SQL：从3列中检索“ Varchar”数据并将其组合在一起

Question

I have three columns in my sql table, "FirstName", "MiddleName","LastName". When retrieving, I need to display these 3 together, for an example

FirstName = "John" MiddleName = "Ned" LastName = "Carter".

On retrieving, these should be displayed as "John Ned Carter".

I tried the following

select FirstName+MiddleName+LastName from PhoneData

There is a problem!!! There are number of Names which the middle name is NULL. There are number of names which the last name is NULL, and so on. This is not retrieving those!!! It simply retrieve names where all the fields are not null!!!! If at least one column is null for a particular name, then it shows the whole name as NULL!!! For an example,

FirstName = "John" MiddleName = NULL LastName = NULL

on retrieval, the out put is ' NULL ' , not "John"

Please help!

Answer 1

Try the ISNULL() function around each field. Then you can set a value for when the selected value is null.

Like this;

select ISNULL(FirstName, '') + ISNULL(MiddleName, '') + ISNULL(LastName, '') from PhoneData