查询的完整格式
SELECT select_expr [,select_expr,...] [
FROM tb_name
[WHERE 条件判断]
[GROUP BY {col_name | postion} [ASC | DESC], ...]
[HAVING WHERE 条件判断]
[ORDER BY {col_name|expr|postion} [ASC | DESC], ...]
[ LIMIT {[offset,]rowcount | row_count OFFSET offset}]
]
- 完整的select语句
select distinct *
from 表名
where ....
group by ... having ...
order by ...
limit start,count
- 执行顺序为：
- from 表名
- where ....
- group by ...
- select distinct *
- having ...
- order by ...
- limit start,count
- 实际使用中，只是语句中某些部分的组合，而不是全部
