MySQL returning an empty result set

Question

I tried doing this in PHP but I got 0 rows returned all the time. Then after some time searching around on StackOverflow, I saw a tip to try doing it in SQL first to see if the results are returned properly.

I tried to do it in SQL and it's returning an empty result set all the time, even tho the values are there.

SQL

SELECT * FROM `serials_table` WHERE `ser_key`='ABCD-EFGH-IJKL-MNOP'

PHP

$result = $link->query("SELECT * FROM serials_table WHERE ser_key='$key'");

Both are returning null value.

ser_key column is set to text type, coallition: utf8_unicode_ci, Null: No, Default: None

The serial key entry is in there and the column 'ser_key' exists as well as the table 'serials_table'. Also I directly copy-pasted the serial key from the table and placed it into the query to avoid any typos.

Did I make some errors with the table structure or something?

I have no idea what to do here, any help would be appreciated.

Try SELECT * FROM serials_table WHERE ser_key like '%ABCD-EFGH-IJKL-MNOP%' to see if it is a trim issue — juergen d
– juergen d, Commented Nov 20, 2013 at 15:19
Can you check if there are hidden spaces in the value field of column ser_key. For example; 'ABCD-EFGH-IJKL-MNOP ' — vonUbisch
– vonUbisch, Commented Nov 20, 2013 at 15:20
@juergend Yes it is working now. How can I avoid that issue from happening again? Also, could you post this as an answer so I can mark it as solved? Thank you very much! — Petar-Krešimir
– Petar-Krešimir, Commented Nov 20, 2013 at 15:23

juergen d · Accepted Answer · 2013-11-20 15:28:19Z

1

When this works

SELECT * FROM serials_table WHERE ser_key like '%ABCD-EFGH-IJKL-MNOP%'

Then you have leading or trailing spaces in your data.

To revert that update your existing table data like this

update serials_table 
set ser_key = trim(ser_key)

After that check where you insert or update the ser_key. In that code segment check if you put only trimmed data in there.

answered Nov 20, 2013 at 15:28

juergen d

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Comments

Mihai · Accepted Answer · 2013-11-20 15:21:55Z

1

Try

SELECT * FROM `serials_table` WHERE TRIM(`ser_key`)='ABCD-EFGH-IJKL-MNOP'

Remove white spaces

UPDATE `serials_table` set `ser_key`= TRIM(`ser_key`);

answered Nov 20, 2013 at 15:21

Mihai

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1 Comment

AdRock Over a year ago

I was about to say to TRIM the input

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