Mar 2, 2015 · An alias can be used in a query select list to give a column a different name. You can use the alias in GROUP BY, ORDER BY, or HAVING clauses to refer to the column. Standard SQL disallows references to column aliases in a WHERE clause.

Aug 21, 2014 · Oracle Database will use this alias in the column heading of the result set. The AS keyword is optional. The alias effectively renames the select list item for the duration of the query. The alias can be used in the order_by_clause but not other clauses in the query.

Jan 6, 2016 · How can I use a column alias somewhere else in the same query? Is it possible in Oracle? Example using EMP_ID: SELECT t1.DATE, t2.NAME, t1.ID, TO_NUMBER( SUBSTR( t1.NUMBER_ID, - 6) ||

The basic syntax for creating a column alias in Oracle is: SELECT column_name AS alias_name. FROM table_name; Alternatively, you can omit the AS keyword, and it will still work: SELECT column_name alias_name. FROM table_name; Example: SELECT first_name AS "Employee Name", salary AS "Salary ($)" FROM employees; In this example:

Summary: in this tutorial, you will learn how to use Oracle alias including column and table aliases to make the heading of the output more meaningful and to improve the readability of a query. When you query data from a table, Oracle uses the column names of the table to display the column heading.

Specifies display attributes for a given column, such as: text for the column heading. alignment for the column heading. format for NUMBER data. wrapping of column data. Also lists the current display attributes for a single column or for all columns. Where option represents one of the following clauses: ALI[AS] alias; CLE[AR]

Feb 2, 2021 · When writing a query, you can use aliases that match the names of other schema objects: create table t as select level c1 from dual connect by level <= 5; create or replace view vw as select count(*) c from t; select vw.* from t vw; C1 1 2 3 4 5 select * from vw; C 5

Aug 17, 2021 · You can't use it that way; either extract "new" ID in a subquery (or a CTE) and then re-use it in "main" query, or - simpler - use it directly in JOIN operation. I used simple substr + instr combination instead of regular expressions (performs better on large data sets).

Jan 7, 2020 · In ORDER BY you can refer to column aliases in the SELECT clause. This is what's happening in query 2. It isn't sorting by the values in the column. It's sorting by the values from the product and country. These are null for the rows displaying TOTAL for product and country. So for product TOTALs it sorts NULL, GB, US, DK.

Mar 24, 2023 · Column Alias renames a column heading in a Query. The column Alias is specified in the SELECT list by declaring the Alias after the column name by using the space separator. Alias heading appears in UPPER casing by default.