sql语句程序执行顺序

1、sql语句(以select语句为例)

SELECT  <select_list> 
FROM <left_table><join_type> JOIN <right_table>  
ON <join_comdition>
WHERE  <where_condition>
GROUP BY <group_by_list>
HAVING <having_condition>
ORGER BY <order_by_condition>
LIMIT <LIMIT_NUMBER>

2、程序执行sql的顺序

1、FROM <left_table>
2、ON <join_condition>
3、JOIN
4、WHERE <where_condition>
5、GROUP BY <group_by_list>
6、HAVING <having_condition>
7、SELECT 
8、DISTINCT <select_list>
9、ORDER_BY <order_by_condition>
10、LIMIT <limit_number>