选择％s作为值字符的查询sql

Question

Hello i'm having a table in a database like this:

╔══════════════════════════════════════════╗
║              v3_url_alias                ║
╠════╦═══════════════╦═════════════════════╣
║ id ║    query      ║       keyword       ║
╠════╬═══════════════╬═════════════════════╣
║  1 ║ product_id=20 ║   540-65R38-K_028   ║
║  2 ║ product_id=21 ║ 18.00R33-EM_DT-150% ║
╚════╩═══════════════╩═════════════════════╝

I'm using this table to make my urls friendly but as many know a % sign ain't a valid url character therefore making my browser getting a bad request. I have a lot of entries in this table (1700 or so) and need a query to grab all the ones with % in the column keyword.

So I've tried doing that in MySQL and came up with this query:

SELECT * FROM v3_url_alias WHERE keyword LIKE '%%%';

This was returning all of my keywords as % is used as a wildcard.

My question how to retrieve every keyword containing a % character with SQL?

Answer 1

Use an escape character!

MySQL has backslash ( \\ ) as default escape character:

SELECT * FROM v3_url_alias WHERE keyword LIKE '%\%%';

The ANSI SQL way is to use an ESCAPE clause to specify escape character, eg:

SELECT * FROM v3_url_alias WHERE keyword LIKE '%#%%' escape '#';

(This works with MySQL too, at least as long as \\ isn't specified.)

Answer 2

Use square brackets.

SELECT * 
FROM v3_url_alias 
WHERE keyword LIKE '%[%]%'

Answer 3

Using MySQL:

Use a backslash to escape character ( \\ ).

SELECT * FROM v3_url_alias WHERE keyword LIKE '%\%%';