MySQL 表和列的别名

表的 SQL Alias 语法

SELECT column_name(s)
FROM table_name
AS alias_name

列的 SQL Alias 语法

SELECT column_name AS alias_name
FROM table_name

子查询和JOIN查询 Alias 语法

SELECT column_name
FROM (

...

) alias_name
WHERE condition

SELECT column_name
FROM table_name
LEFT JOIN right_table_name alias_name ON condition
WHERE condition

SELECT column_name
FROM table_name
LEFT JOIN (
...
) alias_name ON condition
WHERE condition