Search Column after LEFT JOIN - mysql

Question

Currently I have two tables.
Customers:
id
name
status
1
adam
1
2
bob
1
3
cain
2
Orders:
customer_id
item
1
apple
1
banana
1
bonbon
2
carrot
3
egg
I'm trying to do an INNER JOIN first then use the resulting table to query against.
So a user can type in a partial name or partial item and get all the names and items.
For example if a user type in "b" it would kick back:
customer_id
name
status
items
1
adam
1
apple/banana/bonbon
2
bob
1
carrot
What I am currently doing is:
SELECT * FROM(
SELECT customers.* , GROUP_CONCAT(orders.item SEPARATOR '|') as items
FROM customers
LEFT JOIN orders
ON customers.id = orders.customer_id
group by customers.id
) as t
WHERE t.status = 1 AND ( t.name LIKE "%b%" OR t.items LIKE "%b%")
Which does work, but it is incredibly slow (+2 seconds).
The strange part though is if I run the queries individually the subquery executes in .0004 seconds and the outer query executes in .006 seconds.
But for some reason combining them increases the wait time a lot.
Is there a more efficient way to do this?
CREATE TABLE IF NOT EXISTS `customers` (
`id` int(6),
`name` varchar(255) ,
`status` int(6),
PRIMARY KEY (`id`,`name`,`status`)
);
INSERT INTO `customers` (`id`, `name` , `status`) VALUES
('1', 'Adam' , 1),
('2', 'bob' , 1),
('3', 'cain' , 2);
CREATE TABLE IF NOT EXISTS `orders` (
`customer_id` int(6),
`item` varchar(255) ,
PRIMARY KEY (`customer_id`,`item`)
);
INSERT INTO `orders` (`customer_id`, `item`) VALUES
('1', 'apple'),
('1', 'banana'),
('1', 'bonbon'),
('2', 'carrot'),
('3', 'egg');

Answer 1

According to the query, you are trying to perform a full-text search on the fields name and item. I would suggest adding full-text indexes to them using ngram tokenisation as you are looking up by part of a word:
ALTER TABLE customers ADD FULLTEXT INDEX ft_idx_name (name) WITH PARSER ngram;
ALTER TABLE orders ADD FULLTEXT INDEX ft_idx_item (item) WITH PARSER ngram;
In this case, your query would look as follows:
SELECT
customers.*, GROUP_CONCAT(orders.item SEPARATOR '|')
FROM
customers
LEFT JOIN orders on customers.id = orders.customer_id
WHERE
orders.customer_id IS NOT NULL
AND customers.status = 1
AND (MATCH(customers.name) AGAINST('bo')
OR MATCH(orders.item) AGAINST('bo'))
GROUP BY
customers.id
If needed, you could modify ngram_token_size MySQL system variable as its value is 2 by default, which means two or more characters should be input to perform the search.
Another approach is to implement it by means of a dedicated search engine, e.g. Elasticsearch, when requirements evolve.

Answer 2

SELECT * FROM(
SELECT customers.* , GROUP_CONCAT(orders.item SEPARATOR '|') as items
FROM customers
LEFT JOIN orders
ON customers.id = orders.customer_id AND customers.name LIKE "%adam" AND orders.item LIKE "%b"
group by customers.AI
It will be faster to filter the records when starting to left join