问题
I'm trying to find any items in column address (users table) that have a match in Address (address_effect table). I'm testing this on my local system with XAMPP (using MariaDB)
user table
+------------------+-----------------+------------------+--------------------------+
| ID | firstname | lastname | address |
| | | | |
+----------------------------------------------------------------------------------+
| 1 | john | doe |james street, idaho, usa |
| | | | |
+----------------------------------------------------------------------------------+
| 2 | cindy | smith |rollingwood av,lyn, canada|
| | | | |
+----------------------------------------------------------------------------------+
| 3 | rita | chatsworth |arajo ct, fremont, cali |
| | | | |
+------------------+-----------------+---------------------+-----------------------+
| 4 | randy | plies |smith spring, lima, peru |
| | | | |
+----------------------------------------------------------------------------------+
| 5 | Matt | gwalio |park lane, atlanta, usa |
| | | | |
+------------------+-----------------+------------------+--------------------------+
address_effect table
+---------+----------------+
|idaho |potato, tater |
+--------------------------+
|canada |cold, tundra |
+--------------------------+
|fremont | crowded |
+--------------------------+
|peru |alpaca |
+--------------------------+
|atlanta |peach, cnn |
+--------------------------+
|usa |big, hard |
+--------+-----------------+
I've tried using inner join with LIKE to find matching string.
If I use this query it doesn't find any items:
SELECT users.firstname, users.lastname, users.address
FROM users
INNER JOIN db_name.address_effect
ON
(address_effect.Address LIKE '%' + users.address + '%'
OR users.address LIKE '%' || address_effect.Address || '%')
Then I tried the following query, it lists all the items from user table, instead of only those items that have a match in address_effect
SELECT DISTINCT users.firstname, users.lastname, users.address
FROM users
INNER JOIN db_name.address_effect
ON
(address_effect.Address LIKE '%' || users.address || '%'
OR users.address LIKE '%' || address_effect.Address || '%')
What am I missing here?
Thanks.
回答1:
As I understand your sample data, you want to match parts of users addresses against values in the other table.
You might want to try find_in_set(). It is more accurate that a LIKE match, since it matches on individual elements only:
SELECT u.firstname, u.lastname, u.address user_address, a.*
FROM users u
INNER JOIN address_effect a
ON FIND_IN_SET(a.address, REPLACE(u.address, ', ', ','))
This matches if address_effect(address) can be found in the CSV list stored in users(address).
来源：https://stackoverflow.com/questions/62579803/sql-query-to-find-partial-string-match-across-2-tables