Question

What is the most concise way to return CHAR(1) indicator Y/N if one of n columns in a row contain a non-null value?

Performance is important, but not the primary consideration, in this case.

The straightforward way seems to be:

SELECT      CASE WHEN (C.TerminatedDate IS NULL
                       AND C.SelfClosedDate IS NULL
                       AND ...)
                 THEN 'Y'
                 ELSE 'N' END AS 'OpenInd'

  FROM      Customers C

Curious if there is a better way; aware of COALESCE():

SELECT      CASE WHEN COALESCE (C.TerminatedDate, C.SelfClosedDate, ...) IS NULL
                 THEN 'Y'
                 ELSE 'N' END AS 'OpenInd'

  FROM      Customers C

Is there a better way?

Database server is SQL Server 2008.

Answer 1

Since no one is suggesting it, and the question asks for concise..

For the same data types, a straight COALESCE is best

coalesce(a,b,c,d) is not null

If you will be dealing with different data types, try a modified COALESCE

coalesce(LEFT(a,1),LEFT(b,1),LEFT(c,1)) is not null

Sample:

create table abc (a int, b datetime, c varchar(max), d image)
insert into abc select 1, GETDATE(), '', null
insert into abc select 1, null, '', null
insert into abc select 1, null, '', 0x123123
insert into abc select null, null, '', 0x123123
insert into abc select null, GETDATE(), '', 0x123123
insert into abc select null, null, null, null
insert into abc select 88, GETDATE()+3, null, null
insert into abc select 88, GETDATE()+3, 'gdasdf', null
insert into abc select null, null, '222', 0x123123
insert into abc select null, null, 'abcdef', 0x123123

select *, case when coalesce(LEFT(a,1),LEFT(b,1),LEFT(c,1)) is not null then 'N' else 'Y' end
from abc

If you are not using exotic types like VARCHAR(MAX) or IMAGE, then you can use SQL_VARIANT with COALESCE

create table abc (a int, b datetime, c varchar(10), d image)
insert into abc select 1, GETDATE(), '', null
insert into abc select 1, null, '', null
insert into abc select 1, null, '', 0x123123
insert into abc select null, null, '', 0x123123
insert into abc select null, GETDATE(), '', 0x123123
insert into abc select null, null, null, null
insert into abc select 88, GETDATE()+3, null, null
insert into abc select 88, GETDATE()+3, 'gdasdf', null
insert into abc select null, null, '222', 0x123123
insert into abc select null, null, 'abcdef', 0x123123

select *, case when coalesce(convert(sql_variant,a),b,c) is not null then 'N' else 'Y' end
from abc