MySQL LEFT JOIN和ON w / Like-此查询将不会运行，但是匹配存在

Question

Does my query follow correct format? I can't find any examples of using LIKE and ON, so I am not sure if my query is the problem. Looking for any suggestions or feedback:

SELECT * 
FROM table_1 a
LEFT JOIN table_sql ON a.case_id LIKE '%45305%'

Answer 1

This is not correct, you need to specify which column you want to use for the JOIN, but you can do something like this

SELECT * from table_1 AS a
   LEFT JOIN table_sql AS b
   ON a.case_id = b.id
WHERE
   a.case_id LIKE '%45305%'

Answer 2

Since you want to use LIKE instead of = , is this what you want?

SELECT * FROM table_1 a
LEFT JOIN table_sql ON 
 a.case_id LIKE CONCAT('%', table_sql.case_id, '%')

See also #4420554

Answer 3

You can use LIKE in a join, but it sounds like what you you really want is a UNION:

SELECT case_id 
     FROM table_1 a
WHERE a.case_id LIKE '%45305%'
UNION 
SELECT case_id 
     FROM table_sql s
WHERE s.case_id LIKE '%45305%'

If you need to keep track of which table the result came from, you can do something like:

SELECT 'table_a' AS what_table, case_id 
     FROM table_1 a
WHERE a.case_id LIKE '%45305%'
UNION 
SELECT 'table_b', case_id 
     FROM table_sql s
WHERE s.case_id LIKE '%45305%'

Answer 4

Try this, using CONCAT() . it was helpful for me, when I was selecting the full table data:

 SELECT p.post_name,p.post_title,p.post_type,cl.*
FROM ".$wpdb->posts." AS p
LEFT JOIN clicks AS cl
ON cl.podcast_url LIKE CONCAT('%',p.post_name,'%')
WHERE p.post_type = 'team'