SQL查询语句总结

SQL查询语句总结

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

语句的执行顺序

• 
  
• 实际使用中，只是语句中某些部分的组合，而不是全部.
  

• from 表名
  
• where ….
  
• group by …
  
• select distinct *
  
• having …
  
• order by …
  
• limit start,count