Sqlite 简明教程
SQLite - ALIAS Syntax
你可以通过赋予另一个名称，即 ALIAS （称为别名），暂时重命名表或列。使用表别名意在在特定的 SQLite 语句中重命名表。重命名是临时变更，而实际表名称在数据库中不会改变。
You can rename a table or a column temporarily by giving another name, which is known as ALIAS. The use of table aliases means to rename a table in a particular SQLite statement. Renaming is a temporary change and the actual table name does not change in the database.
表别名用于为特定 SQLite 查询的目的重命名表的列。
The column aliases are used to rename a table’s columns for the purpose of a particular SQLite query.
Syntax
以下是 table 别名的基本语法。
Following is the basic syntax of table alias.
SELECT column1, column2....
FROM table_name AS alias_name
WHERE [condition];以下是 column 别名的基本语法。
Following is the basic syntax of column alias.
SELECT column_name AS alias_name
FROM table_name
WHERE [condition];Example
考虑以下两个表，(a) COMPANY 表如下：
Consider the following two tables, (a) COMPANY table is as follows −
sqlite> select * from COMPANY;
ID NAME AGE ADDRESS SALARY
---------- -------------------- ---------- ---------- ----------
1 Paul 32 California 20000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
6 Kim 22 South-Hall 45000.0
7 James 24 Houston 10000.0(b) 另一张表 DEPARTMENT 如下：
(b) Another table is DEPARTMENT as follows −
ID DEPT EMP_ID
---------- -------------------- ----------
1 IT Billing 1
2 Engineering 2
3 Finance 7
4 Engineering 3
5 Finance 4
6 Engineering 5
7 Finance 6现在，以下是 TABLE ALIAS 的用法，其中我们使用 C 和 D 作为 COMPANY 和 DEPARTMENT 表的别名：
Now, following is the usage of TABLE ALIAS where we use C and D as aliases for COMPANY and DEPARTMENT tables respectively −
sqlite> SELECT C.ID, C.NAME, C.AGE, D.DEPT
FROM COMPANY AS C, DEPARTMENT AS D
WHERE C.ID = D.EMP_ID;上述 SQLite 语句将产生以下结果 -
The above SQLite statement will produce the following result −
ID NAME AGE DEPT
---------- ---------- ---------- ----------
1 Paul 32 IT Billing
2 Allen 25 Engineering
3 Teddy 23 Engineering
4 Mark 25 Finance
5 David 27 Engineering
6 Kim 22 Finance
7 James 24 Finance考虑 COLUMN ALIAS 用法的示例，其中 COMPANY_ID 是 ID 列的别名，COMPANY_NAME 是 name 列的别名。
Consider an example for the usage of COLUMN ALIAS where COMPANY_ID is an alias of ID column and COMPANY_NAME is an alias of name column.
sqlite> SELECT C.ID AS COMPANY_ID, C.NAME AS COMPANY_NAME, C.AGE, D.DEPT
FROM COMPANY AS C, DEPARTMENT AS D
WHERE C.ID = D.EMP_ID;上述 SQLite 语句将产生以下结果 -
The above SQLite statement will produce the following result −
COMPANY_ID COMPANY_NAME AGE DEPT
---------- ------------ ---------- ----------
1 Paul 32 IT Billing
2 Allen 25 Engineering
3 Teddy 23 Engineering
4 Mark 25 Finance
5 David 27 Engineering
6 Kim 22 Finance
7 James 24 Finance