如何优化产品取数查询

Question

我已经使用了下面的产品列表查询。查询工作正常，但大约需要0.4534秒。如何优化相同的查询。

SELECT SQL_CALC_FOUND_ROWS DISTINCT tp.prod_id, tp.prod_name, tp.prod_shop, tp.prod_retail_price, tp.prod_sale_price, tp.prod_initial_price, tp.prod_stock, ts.shop_id, ts.shop_name, ts.shop_logo, ts.shop_description, ts.shop_title, tu.user_profile_image, ( SELECT pdiscount_price FROM tbl_product_discounts tpd WHERE tpd.pdiscount_product_id = tp.prod_id AND tpd.pdiscount_qty = '1' AND( ( tpd.pdiscount_start_date = '0000-00-00' OR tpd.pdiscount_start_date < NOW()) AND( tpd.pdiscount_end_date = '0000-00-00' OR tpd.pdiscount_end_date > NOW()) ) ORDER BY tpd.pdiscount_priority ASC, tpd.pdiscount_price ASC LIMIT 1 ) AS discount FROM tbl_products tp LEFT JOIN tbl_shops ts ON tp.prod_shop = ts.shop_id AND ts.shop_is_deleted = 0 INNER JOIN tbl_users tu ON ts.shop_user_id = tu.user_id WHERE tp.prod_is_deleted = '0' LIMIT 0, 20

Answer 1

不检查您的表或要求：

如果可能，

1. 尝试使用group by而不是sub query。
2. 尝试在您的表中使用索引。

这将帮助您优化查询。