Define and Use Table Alias Names in Oracle

Q

How To Define and Use Table Alias Names in Oracle?

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A

When column names need to be prefixed with table names, you can define table alias name and use them to prefix column names as shown in the following select statement:

SQL> SELECT e.first_name, e.last_name, d.department_name
  FROM employees e INNER JOIN departments d 
  ON e.department_id=d.department_id;
FIRST_NAME           LAST_NAME            DEPARTMENT_NAME
-------------------- -------------------- ---------------
Steven               King                 Executive
Neena                Kochhar              Executive
Lex                  De Haan              Executive
Alexander            Hunold               IT
Bruce                Ernst                IT
David                Austin               IT
Valli                Pataballa            IT
......

⇒ Query with a Left Outer Join in Oracle

⇐ Query with an Inner Join in Oracle

⇑ Understanding SQL SELECT Query Statements in Oracle

⇑⇑ Oracle Database Tutorials

2019-10-27, 3215🔥, 0💬

Query with a Left Outer Join in Oracle
How To Write a Query with a Left Outer Join in Oracle? If you want to query from two tables with a left outer join, you can use the LEFT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a left outer join from two tables: departments and employees. The join conditi... 2019-10-18, 3238🔥, 0💬

Define and Use Table Alias Names in Oracle
How To Define and Use Table Alias Names in Oracle? When column names need to be prefixed with table names, you can define table alias name and use them to prefix column names as shown in the following select statement: SQL> SELECT e.first_name, e.last_name, d.department_name FROM employees e ... 2019-10-27, 3216🔥, 0💬

Query with an Inner Join in Oracle
How To Write a Query with an Inner Join in Oracle? If you want to query from two tables with an inner join, you can use the INNER JOIN ... ON clause in the FROM clause. The following query returns output with an inner join from two tables: employees and departments. The join condition is that the de... 2019-10-27, 3178🔥, 0💬

Query with a Full Outer Join in Oracle
How To Write a Query with a Full Outer Join in Oracle? If you want to query from two tables with a full outer join, you can use the FULL OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a full outer join from two tables: departments and employees. The join conditi... 2019-10-18, 3175🔥, 0💬

Inner Join with the WHERE Clause in Oracle
How To Write an Inner Join with the WHERE Clause in Oracle? If you don't want to use the INNER JOIN ... ON clause to write an inner join, you can put the join condition in the WHERE clause as shown in the following query example: SQL> SELECT d.department_name, e.first_name, e.last_name 2 FROM... 2019-10-18, 3114🔥, 0💬

Left Outer Join with the WHERE Clause in Oracle
How To Write a Left Outer Join with the WHERE Clause in Oracle? If you don't want to use the LEFT OUTER JOIN ... ON clause to write a left outer join, you can use a special criteria in the WHERE clause as "left_table.column = right_table.column(+)". The select statement below is an example of a left... 2019-10-18, 3027🔥, 0💬

Query with a Right Outer Join in Oracle
How To Write a Query with a Right Outer Join in Oracle? If you want to query from two tables with a right outer join, you can use the RIGHT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a right outer join from two tables: departments and employees. The join con... 2019-10-18, 2912🔥, 0💬

Use Group Functions in ORDER BY Clause in Oracle
Can Group Functions Be Used in the ORDER BY Clause in Oracle? If the query output is aggregated as groups, you can sort the groups by using group functions in the ORDER BY clause. The following statement returns how many employees are having the same salary in each department. The group output is so... 2019-10-27, 2900🔥, 0💬

Count Duplicated Values in a Column in Oracle
How To Count Duplicated Values in a Column in Oracle? If you have a column with duplicated values, and you want to know what are those duplicated values are and how many duplicates are there for each of those values, you can use the GROUP BY ... HAVING clause as shown in the following example. It re... 2019-11-21, 2847🔥, 0💬

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