人写的 SQL 语句 ：
SELECT DISTINCT
< select_list >
FROM
< left_table > < join_type >
JOIN < right_table > ON < join_condition >
WHERE
< where_condition >
GROUP BY
< group_by_list >
HAVING
< having_condition >
ORDER BY
< order_by_condition >
LIMIT < limit_number >
机器读取 SQL 的顺序 ：
1
FROM <left_table>
2
ON <join_condition>
3
<join_type> JOIN <right_table>
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>
SQL 解析顺序 ：
