MySQL的操作顺序？

Question

是否有明确的地方可以找到 mySQL 语句的操作顺序？下面的顺序正确吗？

FROM 子句 WHERE 子句 GROUP BY 子句 HAVING 子句 SELECT 子句 ORDER BY 子句

如果是这种情况，我可以在 group by 子句中使用 SELECT 类中定义的术语（选择 first_name 作为“f_name”）吗？

谢谢！

Answer 1

我假设您感兴趣SELECT，根据MySQL 文档，语法如下

SELECT
[ALL | DISTINCT | DISTINCTROW ]
  [HIGH_PRIORITY]
  [STRAIGHT_JOIN]
  [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
  [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
select_expr [, select_expr ...]
[FROM table_references
[WHERE where_condition]
[GROUP BY {col_name | expr | position}
  [ASC | DESC], ... [WITH ROLLUP]]
[HAVING where_condition]
[ORDER BY {col_name | expr | position}
  [ASC | DESC], ...]
[LIMIT {[offset,] row_count | row_count OFFSET offset}]
[PROCEDURE procedure_name(argument_list)]
[INTO OUTFILE 'file_name' export_options
  | INTO DUMPFILE 'file_name'
  | INTO var_name [, var_name]]
[FOR UPDATE | LOCK IN SHARE MODE]]

是的，您可以使用AS在GROUP BY子句中定义的列。