SQL Tip: Find all The Rows Where Any Of The Columns Is Null Or Zero Or Both

This question is asked every now and then so I decided to do a little blog post. How can you quickly without writing a bunch of OR statements determince if any columns have a NULL value, a value of 0 or if the value is 0 or NULL.
To test for NULL is very easy, you just concatenate the columns since NULL + anything else is always NULL. Okay that also depends on a setting.

Run this

SET CONCAT_NULL_YIELDS_NULL ON
SELECT NULL + '1' --NULL

SET CONCAT_NULL_YIELDS_NULL OFF
SELECT NULL + '1' --1

As you can see if CONCAT_NULL_YIELDS_NULL is OFF then the result is 1

Now take a look at this


SET CONCAT_NULL_YIELDS_NULL ON
SELECT NULL + 1 --NULL



SET CONCAT_NULL_YIELDS_NULL OFF
SELECT NULL + 1 --NULL


So with numeric values it behaves differently. Either way by default CONCAT_NULL_YIELDS_NULL is set to on
To test for NULLS or zeroes you use NULLIF
To test for zeros you can combine COALESCE and NULLIF

Here is the code which shows all of that

CREATE TABLE #test(column1 int,column2 varchar(4),column3 float)

INSERT #test VALUES(2,'2',2)
INSERT #test VALUES(0,'1',0)
INSERT #test VALUES(null,'1',0)
INSERT #test VALUES(1,null,0)
INSERT #test VALUES(0,'1',null)
INSERT #test VALUES(null,null,null)



--Any column is Null
SELECT * FROM #test
WHERE column1 + column2+column3 is null

Output
------------
NULL 1 0.0
1 NULL 0.0
0 1 NULL
NULL NULL NULL



--Any column is Null or zero
SELECT * FROM #test
WHERE NULLIF(column1,0) + NULLIF(column2,0)+NULLIF(column3,0) is null

Output
-------------------
0 1 0.0
NULL 1 0.0
1 NULL 0.0
0 1 NULL
NULL NULL NULL




--Any column is zero
SELECT * FROM #test
WHERE NULLIF(COALESCE(column1,1),0) +
NULLIF(COALESCE(column2,1),0)+
NULLIF(COALESCE(column3,1),0) is null

Output
-------------------
0 1 0.0
NULL 1 0.0
1 NULL 0.0
0 1 NULL


DROP TABLE #test