mysql5.7可以在group by 、having、order by中使用别名，但是有where 不可以

select count(1) a,substr(landlord_name,1,2) as c from mjc_lease_details d
GROUP BY c having c like '丁%' order by c

等价于

select count(1) a,substr(landlord_name,1,2) as c from mjc_lease_details d
GROUP BY substr(landlord_name,1,2) having substr(landlord_name,1,2) like '丁%' order by substr(landlord_name,1,2)

select count(1) a,substr(landlord_name,1,2) as c from mjc_lease_details d
where c like '丁%'
GROUP BY c  order by c

例如像hive，Oracle这种并不支持这种写法，所以尽量还是写规范点，套一层子查询