MySQL EXISTS return 1 or 0

Question

How can I return the 1 or 0 as true and false for my select query? I've tried every combination of fetch_assoc, arrays, etc. It usually returns as null, which doesn't make sense.

$querydetails = "select exists (select * from customer_det where id = $uid)";
$resultdetails = mysql_query($querydetails) or die(mysql_error());
while ($row = mysql_fetch_assoc($resultdetails)) {
    $resultdetails1 = $row[0];
}

That's the latest version of my query. I guess it's not an array, but I'm not sure how to pull the value if there's no row to be named?

This is a post question to my previous thread: MySQL Update WHERE

possible duplicate of [The quick way to check if SELECT EXISTS(...) returns a value, using PHP?](http://stackoverflow.com/questions/4484974/the-quick-way-to-check-if-select-exists-returns-a-value-using-php) — Anirudh Ramanathan, Nov 01 '12 at 13:41
You should switch to mysqli, mysql is deprecated. That means there is no support for it from now on, a better version exists, and people here will get mad if you post a question that is using it. — Asad Saeeduddin, Nov 01 '12 at 13:41
I apologize is this is a duplicated question, I did not see that question posted. Nonetheless, I can return a 1 or a 0 while inserting that into the SQL query of phpMyAdmin, but I can't get it to return with the PHP — smada, Nov 01 '12 at 13:44
@asad The php version running on the server does not support mysqli. I realize this is an issue, but hopefully someone will be updating it in the future. — smada, Nov 01 '12 at 13:44

score 9 · Accepted Answer · answered Nov 01 '12 at 13:40

9

SELECT IF(EXISTS(...),1,0) AS result

answered Nov 01 '12 at 13:40

dev-null-dweller

29,274
3
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85

score 3 · Answer 2 · answered Nov 01 '12 at 13:43

3

simple use COUNT and IF

SELECT IF(COUNT(*) = 0, 0, 1)
FROM table1
WHERE s = 2

SQLFiddle Demo

answered Nov 01 '12 at 13:43

John Woo

258,903
69
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492

EXISTS can do this without count. Simply use a LIMIT 1 clause inside a subquery. – Anthony Rutledge Jan 02 '17 at 22:29

score 0 · Answer 3 · answered Jan 15 '22 at 08:34

0

SELECT count(*) FROM (
 SELECT id FROM table WHERE condition LIMIT 1
) AS result;

answered Jan 15 '22 at 08:34

Luciano Aibar

1

score 0 · Answer 4 · answered Nov 02 '22 at 02:37

0

i am using mysql version 8.0.23 on AMS

SELECT
column1,
column2,
IF (exists(select * from MeasurementItemNos measureItem where measureItem.itemNo = ib.itemNo and measureItem.IsActive = 1),1,0) as isUploadedSizeSpec
from table

answered Nov 02 '22 at 02:37

Keith POON

86
6

score -1 · Answer 5 · answered Nov 01 '12 at 13:43

-1

I would do:

select * from customer_det where id = $uid LIMIT 1

You will get either 1 row or zero rows.

answered Nov 01 '12 at 13:43

Brian

8,418
2
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You will more likely get one actual row of data, or the empty set. – Anthony Rutledge Jan 02 '17 at 22:31

MySQL EXISTS return 1 or 0

5 Answers5

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