Du kanske vill prova följande:
SELECT CONCAT(title, ' ', forename, ' ', surname) AS name
FROM customer c
JOIN (
SELECT MAX(id) max_id, customer_id
FROM customer_data
GROUP BY customer_id
) c_max ON (c_max.customer_id = c.customer_id)
JOIN customer_data cd ON (cd.id = c_max.max_id)
WHERE CONCAT(title, ' ', forename, ' ', surname) LIKE '%Smith%'
LIMIT 10, 20;
Observera att en JOIN
är bara en synonym för INNER JOIN
.
Testfall:
CREATE TABLE customer (customer_id int);
CREATE TABLE customer_data (
id int,
customer_id int,
title varchar(10),
forename varchar(10),
surname varchar(10)
);
INSERT INTO customer VALUES (1);
INSERT INTO customer VALUES (2);
INSERT INTO customer VALUES (3);
INSERT INTO customer_data VALUES (1, 1, 'Mr', 'Bobby', 'Smith');
INSERT INTO customer_data VALUES (2, 1, 'Mr', 'Bob', 'Smith');
INSERT INTO customer_data VALUES (3, 2, 'Mr', 'Jane', 'Green');
INSERT INTO customer_data VALUES (4, 2, 'Miss', 'Jane', 'Green');
INSERT INTO customer_data VALUES (5, 3, 'Dr', 'Jack', 'Black');
Resultat (fråga utan LIMIT
och WHERE
):
SELECT CONCAT(title, ' ', forename, ' ', surname) AS name
FROM customer c
JOIN (
SELECT MAX(id) max_id, customer_id
FROM customer_data
GROUP BY customer_id
) c_max ON (c_max.customer_id = c.customer_id)
JOIN customer_data cd ON (cd.id = c_max.max_id);
+-----------------+
| name |
+-----------------+
| Mr Bob Smith |
| Miss Jane Green |
| Dr Jack Black |
+-----------------+
3 rows in set (0.00 sec)