MySQL的SELECT与SUBSTRING，LOWER和REPLACE命令

Question

Im trying to do a select on the company name(cpnm) field of our company table but only giving me the first 6 characters, replacing all spaces plus making it lowercase.

SELECT *,
SUBSTRING(LOWER(cpnm), -LENGTH(cpnm), 6) as test
FROM company
LIMIT 100

The above works fine but as soon as I try to add the replace spaces (shown below), it doesnt give back results.

SELECT *,
SUBSTRING(LOWER(REPLACE(cpnm, ' ', '')), -LENGTH(cpnm), 6) as test
FROM company
LIMIT 100

Any ideas?

Answer 1

I guess by replacing the spaces you change the length of the string, therefore substr() doesn't work like you expect it.

Try SELECT *, SUBSTRING(LOWER(REPLACE(cpnm, ' ', '')), -LENGTH(REPLACE(cpnm, ' ', '')), 6) as test instead!