MySql心得：

1.insert select from

INSERT INTO individuals_id (id, param, flag) 
SELECT
    id,
    1 AS param,
    0 AS flag
FROM
    entities_copy
WHERE
    LENGTH(id) > 0

2.不同表之间update

UPDATE entities a,
 entities_industries b
SET a.industries = b.industries
WHERE
    a.id = b.id
AND LENGTH(b.industries) > 0

4.提高性能的表写入操作

--锁表
LOCK TABLES `order` WRITE;
--禁用键
ALTER TABLE `order` DISABLE KEYS ;
--插入数据
INSERT INTO `order` VALUES (1,11,'UPDATED');
INSERT INTO `order` VALUES (2,11,'UPDATED');
--启用键
 ALTER TABLE `order` ENABLE KEYS; 
--解锁表 
UNLOCK TABLES;