using a regex to remove invalid values from image - mysql

Question

working on a code where we are storing images but some images ending with weird characters
like , %2C -x1 to x10 etc or more but always end wih a .jpg
how can i regex to replace the image name to be a valid name
here is an example of what i have
PCpaste_10_g,-X1,-X2,-X3
SNBar_NEW,-X1
they can go till -X10
so i want to have regex to remove ,and everything afterwards it
i tried using replace but that only works for one item at a time

Answer 1

If your data is consistent with the string before the first comma that need to be taken, then you can try with SUBSTRING_INDEX;
Let's use this as you sample table & using your sample data:
CREATE TABLE mytable (
val VARCHAR(255));
INSERT INTO mytable VALUES
('PCpaste_10_g,-X1,-X2,-X3.jpg'),
('SNBar_NEW,-X1.jpg');
val
PCpaste_10_g,-X1,-X2,-X3.jpg
SNBar_NEW,-X1.jpg
Then first you extract the first string before comma occurrence:
SELECT SUBSTRING_INDEX(val,',',1) extracted
FROM mytable
returns
extracted
PCpaste_10_g
SNBar_NEW
Then to add back .jpg:
SELECT CONCAT(SUBSTRING_INDEX(val,',',1),'.jpg') extracted_combined
FROM mytable
IF your image extension is not consistently .jpg, you can do another SUBSTRING_INDEX() to get the extension then CONCAT() them:
SELECT CONCAT(SUBSTRING_INDEX(val,',',1) ,'.',
SUBSTRING_INDEX(val,'.',-1)) Extracted_combined
FROM mytable;
Demo fiddle

Answer 2

You can use LOCATE to find the first occurrence of "," in the field and LEFT to grab everything up to the first "," -
SET #value := 'PCpaste_10_g,-X1,-X2,-X3';
SELECT CONCAT(LEFT(#value, LOCATE(',', #value) - 1), '.jpg');
or for your update -
UPDATE <table>
SET image_name = CONCAT(LEFT(image_name, LOCATE(',', image_name) - 1), '.jpg')
WHERE image_name LIKE '%,%';
or to handle your %2C at the same time -
UPDATE <table>
SET image_name = CASE
WHEN image_name LIKE '%,%'
THEN CONCAT(LEFT(image_name, LOCATE(',', image_name) - 1), '.jpg')
WHEN image_name LIKE '%\%2C%'
THEN CONCAT(LEFT(image_name, LOCATE('%2C', image_name) - 1), '.jpg')
END
WHERE image_name LIKE '%,%'
OR image_name LIKE '%\%2C%';