如何在Milion Record MySQL上加快UNION TABLE查询？

Question

这是我的查询

SELECT * FROM (
        SELECT simple_sku, picture_url, product_name, discounted_price, tracking_link, 'Lazada.co.id' AS table_identity
        FROM `list_lazada`
        UNION
        SELECT id_product, picture_url, product_name, sale_price, tracking_link, 'Simulation.com' AS table_identity
        FROM `list_simulation`
    ) AS big_table
    WHERE product_name LIKE '%$search%' ORDER BY big_table.discounted_price ASC
    LIMIT 12 ";

现在使用phpmyadmin开发php。

每张桌子只有4列

如何使其更快？

Answer 1

您不需要外部子查询：

SELECT simple_sku, picture_url, product_name, discounted_price, tracking_link,
       'Lazada.co.id' AS table_identity
FROM `list_lazada`
UNION
SELECT id_product, picture_url, product_name, sale_price, tracking_link,
       'Simulation.com' AS table_identity
FROM `list_simulation`
WHERE product_name LIKE '%$search%'
ORDER BY discounted_price ASC
LIMIT 12

我认为您的LIKE条件将导致product_name列上的索引不可用，从而导致全表扫描。 但是也许您可以改善搜索方法以利用索引。