Check whether a column is empty

Question

I need to retrieve columns of a row that one of its data types is empty. Extra VARCHAR Extra has nothing in it

Show those with empty extra column

  Select * FROM Items WHERE Extra ?????

What should be the condition ?

score 4 · Accepted Answer · answered Sep 18 '12 at 15:00

4

Check whether it is null or empty string.

 Select * FROM Items WHERE Extra IS NULL OR Extra = ''

answered Sep 18 '12 at 15:00

xdazz

1

Here's a good habit to get into... Put all ORs in parens. The first time you try to edit a `WHERE` clause with an `OR`, you'll appreciate them... – Alain Collins Sep 18 '12 at 17:30

score 2 · Answer 2 · edited Sep 18 '12 at 15:21

2

select * from items where Isnull(extra,'')=''

edited Sep 18 '12 at 15:21

the Tin Man

answered Sep 18 '12 at 15:17

khurram amin

score 1 · Answer 3 · edited May 23 '17 at 12:23

1

If empty means "" or empty string then:

select * from items where extra="";

The length of empty string is zero/0 .

If empty means NULL then:

select * from items where extra is NULL;

The length of NULL is NULL.

If you want to read more, you can read these:

edited May 23 '17 at 12:23

Community

answered Sep 18 '12 at 15:09

cola

score 0 · Answer 4 · answered Sep 18 '12 at 15:00

0

Select * 
FROM Items 
WHERE Extra IS NULL

answered Sep 18 '12 at 15:00

Mahmoud Gamal

score 0 · Answer 5 · edited Sep 18 '12 at 15:22

0

If you by empty mean NULL...

Select * FROM Items WHERE Extra IS NULL

edited Sep 18 '12 at 15:22

the Tin Man

answered Sep 18 '12 at 15:02

Daniel Persson

score -1 · Answer 6 · answered Sep 18 '12 at 15:01

-1

Select empty varchar fields, with either an empty string or NULL in it:

SELECT * FROM `Items` WHERE `Extra` < 1;

answered Sep 18 '12 at 15:01

feeela

If 'extra' is null, your express will return null, and no row will be returned. Plus it's typecasting everything, and is hard to read. – Alain Collins Sep 18 '12 at 17:29

6 Answers6