Find and replace '000L' from all rows - mysql

Question

I'm trying to remove certain letters from part numbers but I'm having difficulties trying to get it working correctly.
This is where I'm at right now. It's non functional.
SELECT REPLACE(`part`, '[0-9]L', '') FROM `table` WHERE (`part ` LIKE '%[0-9]L')
Essentially say I have these five items:
D39J02GEN
20F934L
2984CPL
29048L20GEN
1120934L
I only want the ones in bold to be detected. So where they end in L, only if they have a number before the L.
Edit: this one gets close:
SELECT * FROM `table ` WHERE `part` REGEXP '^[0-9].*L';
but still shows ones where there is anything after the L. This is also no closer to removing the letter L.

Answer 1

If you know the value is at the end, then do:
SELECT LEFT(part, LENGTH(part) - 2)
FROM `table`
WHERE part REGEXP '[0-9]L$';
This would be much trickier if the pattern were in the middle of the string.

Answer 2

Something like this should also work if the match is always required at the end of the text.
Query
SELECT
*
FROM
t
WHERE
SUBSTRING(REVERSE(t.text_string), 1, 1) = 'L'
AND
SUBSTRING(REVERSE(t.text_string), 2) >> 0 <> 0
Result
| text_string |
| ----------- |
| 20F934L |
| 1120934L |
see demo
Note
SUBSTRING(REVERSE(t.text_string), 2) >> 0 basically means CAST(SUBSTRING(REVERSE(t.text_string), 2) AS UNSIGNED) here
Why this works?
I use MySQL's loose autocasting feature which can convert 439F02 in a INT 439 but it can't convert PC4892 into a INT it would be converted into 0
See the below resultset based on the query
Query
SELECT
*
, SUBSTRING(REVERSE(t.text_string), 1, 1)
, SUBSTRING(REVERSE(t.text_string), 2)
, SUBSTRING(REVERSE(t.text_string), 2) >> 0
, SUBSTRING(REVERSE(t.text_string), 2) >> 0 <> 0
FROM
t
Result
| text_string | SUBSTRING(REVERSE(t.text_string), 1, 1) | SUBSTRING(REVERSE(t.text_string), 2) | SUBSTRING(REVERSE(t.text_string), 2) >> 0 | SUBSTRING(REVERSE(t.text_string), 2) >> 0 <> 0 |
| ----------- | --------------------------------------- | ------------------------------------ | ----------------------------------------- | ---------------------------------------------- |
| D39J02GEN | N | EG20J93D | 0 | 0 |
| 20F934L | L | 439F02 | 439 | 1 |
| 2984CPL | L | PC4892 | 0 | 0 |
| 29048L20GEN | N | EG02L84092 | 0 | 0 |
| 1120934L | L | 4390211 | 4390211 | 1 |
Here is a demo to see the above results for yourself.