May 16, 2021 SQLite
You can temporarily rename a table or column to another name, which is called an alias. U sing a table alias refers to renaming a table in a specific SQLite statement. Renaming is a temporary change, and the name of the actual table in the database does not change.
Column alias is used to rename columns in a table for a particular SQLite statement.
Table The basic syntax of the alias is as follows:
SELECT column1, column2.... FROM table_name AS alias_name WHERE [condition];
The basic syntax of the column alias is as follows:
SELECT column_name AS alias_name FROM table_name WHERE [condition];
Suppose you have two tables, (1) the COMPANY table looks like this:
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
(2) The other table is THED, 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
Now, here's how to use the table alias, where we use C and D as the alias for the 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;
The SQLite statement above produces the following result:
ID NAME AGE DEPT ---------- ---------- ---------- ---------- 1 Paul 32 IT Billing 2 Allen 25 Engineerin 3 Teddy 23 Engineerin 4 Mark 25 Finance 5 David 27 Engineerin 6 Kim 22 Finance 7 James 24 Finance
Let's look at an example of a column alias, where COMPANY_ID is an alias for an ID column and COMPANY_NAME is an alias for a 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;
The SQLite statement above produces the following result:
COMPANY_ID COMPANY_NAME AGE DEPT ---------- ------------ ---------- ---------- 1 Paul 32 IT Billing 2 Allen 25 Engineerin 3 Teddy 23 Engineerin 4 Mark 25 Finance 5 David 27 Engineerin 6 Kim 22 Finance 7 James 24 Finance