How to effectively use func.isnull in sql alchemy to get the two strings joined comma separated?

Question

Below is the code I have as part of a sqlalchemy query. Most of the time fist name is null. But Here in the case of below statement, always returns last name with a comma. Eg: lastName, How to add comma only if there's first name?

(func.isnull(
            prv.last_name,
            '') +
         ', ' +
         func.isnull(
            prv.first_name,
            '')).label('MyName')

score 1 · Answer 1 · answered Sep 17 '19 at 07:13

I don't know what database you use behind sqlalchemy but I believe what you are looking for is an equivalent of MySQL's CONCAT_WS

CONCAT_WS() stands for Concatenate With Separator and is a special form of CONCAT(). The first argument is the separator for the rest of the arguments. The separator is added between the strings to be concatenated. The separator can be a string, as can the rest of the arguments. If the separator is NULL, the result is NULL.

Using it in sqlalchemy should be a matter of calling

func.CONCAT_WS(',', prv.last_name,prv.first_name) (example)

How to effectively use func.isnull in sql alchemy to get the two strings joined comma separated?

1 Answers1