MySQL CONCAT returns NULL if any field contain NULL

Question

I have following data in my table \"devices\"

affiliate_name  affiliate_location  model     ip             os_type    os_version 

cs1             inter             


        

Answer 1

CONCAT_WS still produces null for me if the first field is Null. I solved this by adding a zero length string at the beginning as in

CONCAT_WS("",`affiliate_name`,'-',`model`,'-',`ip`,'-',`os_type`,'-',`os_version`)

however

CONCAT("",`affiliate_name`,'-',`model`,'-',`ip`,'-',`os_type`,'-',`os_version`) 

produces Null when the first field is Null.

Answer 2

you can use if statement like below

select CONCAT(if(affiliate_name is null ,'',affiliate_name),'- ',if(model is null ,'',affiliate_name)) as model from devices

Answer 3

convert the NULL values with empty string by wrapping it in COALESCE

SELECT CONCAT(COALESCE(`affiliate_name`,''),'-',COALESCE(`model`,''),'-',COALESCE(`ip`,''),'-',COALESCE(`os_type`,''),'-',COALESCE(`os_version`,'')) AS device_name
FROM devices

Answer 4

SELECT CONCAT(isnull(`affiliate_name`,''),'-',isnull(`model`,''),'-',isnull(`ip`,''),'-',isnull(`os_type`,''),'-',isnull(`os_version`,'')) AS device_name
FROM devices

Answer 5

To have the same flexibility in CONCAT_WS as in CONCAT (if you don't want the same separator between every member for instance) use the following:

SELECT CONCAT_WS("",affiliate_name,':',model,'-',ip,... etc)

Answer 6

Use CONCAT_WS instead:

CONCAT_WS() does not skip empty strings. However, it does skip any NULL values after the separator argument.

SELECT CONCAT_WS('-',`affiliate_name`,`model`,`ip`,`os_type`,`os_version`) AS device_name FROM devices