我有这个查询: -
SELECT SUM(DISTINCT( ttagrels.id_tag IN ( 1816, 2642, 1906, 1398,
2436, 2940, 1973, 2791, 1389 ) )) AS
key_1_total_matches,
IF(( od.id_od > 0 ), COUNT(DISTINCT( od.id_od )), 0) AS
tutor_popularity,
td.*,
u.*
FROM tutor_details AS td
JOIN users AS u
ON u.id_user = td.id_user
JOIN all_tag_relations AS ttagrels
ON td.id_tutor = ttagrels.id_tutor
LEFT JOIN learning_packs AS lp
ON ttagrels.id_lp = lp.id_lp
LEFT JOIN learning_packs_categories AS lpc
ON lpc.id_lp_cat = lp.id_lp_cat
LEFT JOIN learning_packs_categories AS lpcp
ON lpcp.id_lp_cat = lpc.id_parent
LEFT JOIN learning_pack_content AS lpct
ON ( lp.id_lp = lpct.id_lp )
LEFT JOIN webclasses AS wc
ON ttagrels.id_wc = wc.id_wc
LEFT JOIN learning_packs_categories AS wcc
ON wcc.id_lp_cat = wc.id_wp_cat
LEFT JOIN learning_packs_categories AS wccp
ON wccp.id_lp_cat = wcc.id_parent
LEFT JOIN order_details AS od
ON td.id_tutor = od.id_author
LEFT JOIN orders AS o
ON od.id_order = o.id_order
WHERE ( u.country = 'IE'
OR u.country IN ( 'INT' ) )
AND u.status = 1
AND CASE
WHEN ( lp.id_lp > 0 ) THEN lp.id_status = 1
AND lp.published = 1
AND lpcp.status = 1
AND ( lpcp.country_code = 'IE'
OR lpcp.country_code IN ( 'INT' )
)
ELSE 1
END
AND CASE
WHEN ( wc.id_wc > 0 ) THEN wc.wc_api_status = 1
AND wc.id_status = 1
AND wc.wc_type = 0
AND
wc.class_date > '2010-06-16 11:44:40'
AND wccp.status = 1
AND ( wccp.country_code = 'IE'
OR wccp.country_code IN ( 'INT' )
)
ELSE 1
END
AND CASE
WHEN ( od.id_od > 0 ) THEN od.id_author = td.id_tutor
AND o.order_status = 'paid'
AND CASE
WHEN ( od.id_wc > 0 ) THEN od.can_attend_class = 1
ELSE 1
END
ELSE 1
END
AND ( ttagrels.id_tag IN ( 1816, 2642, 1906, 1398,
2436, 2940, 1973, 2791, 1389 ) )
GROUP BY td.id_tutor
HAVING key_1_total_matches = 1
ORDER BY tutor_popularity DESC,
u.surname ASC,
u.name ASC
LIMIT 0, 20
IN() 中的数字实际上是另一个名为 Tags 的表的 ID,它与用户输入的搜索关键字匹配。在此示例中,用户搜索了“类”。
在此处查看此查询的解释输出:- http://www.test.examvillage.com/Screenshot.png
此查询所用时间为 0.0536 秒
但是,如果 () 中的 ttagrels.id_tag 中的值的数量增加(随着用户输入更多搜索关键字),执行时间会上升到大约 1-5 秒甚至更多。例如,如果用户搜索“课程可供导师和学生每天 3 次”
执行时间为 4.2226 秒。此查询的解释查询输出包含 2513 行。
All_Tag_Relations 表中共有 6,152 条记录。是否可以进一步优化?