根本的优化之道还的从SQL语句出发。
SQL模板:
(1) FROM <LEFT_TABLE> <JOIN_TYPE>
(2) JOIN <RIGHT_TABLE>
(3) ON <JOIN_CONDITION>
(4) WHERE <WHERE_CONDITION>
(5) GROUP BY
(6) WITH <CUBE|ROLLUP>
(7) HAVING <HAVING_CONDITION>
(8) SELECT
(9) DISTINCT <SELECT_LIST>
(10) ORDER BY <ORDER_BY_LIST>
(11) LIMIT <LIMIT_NUMBER>
JOIN_TYPE -< LEFT OUTER JOIN , INNER JOIN>
- 减少查询字段数
- 表关联尽量用主键
- 查询条件尽量避免模糊查询
- 避免使用排序字段,排序字段尽量使用主键
- 尽量使用限制查询条件
- 查询条件使用有效索引