使用doris过程中总结的与mysql中语法差异

1.mysql中的varchar()长度与doris中长度不一致，导致导入失败

2.doris中 where后面 时间与字符串比较 需转化类型

#当create_time为datetime类型，mysql中使用concat()函数可直接比较，doris则不行，需进行类型转化
where date_format(create_time,'%Y-%m-%d %H:%i:%s')<= concat('2021-10-21','23:59:59')
or
where cast(create_time as String)<= concat('2021-10-21','23:59:59')

3.doris 中编写sql不支持 #注释 例:

select HEX(date_format('2021-10-21 23:59:59','%Y-%m-%d %H:%i:%s') )  #存储编码  错误

select HEX(date_format('2021-10-21 23:59:59','%Y-%m-%d %H:%i:%s') ) --存储编码  正确

4.mysql中支持部分多表联查分组后跟部分字段，doris需将查询字段都放在分组条件后

SELECT
mb.market_id,
mk.market_name
FROM
members as mb,
market as mk
WHERE
mb.market_id = mk.id
GROUP BY
mb.market_id

--doris查询所有字段需在group by后
SELECT
mb.market_id,
mk.market_name
FROM
members as mb,
market as mk
WHERE
mb.market_id = mk.id
GROUP BY
mb.market_id,mk.market_name

5.mysql中 where 后可直接 locate() 判断，doris中需判断

--mysql
where locate(id,market_id)
--doris
where locate(id,market_id) > 0