How To Use Subqueries with the IN Operator

Q

How To Use Subqueries with the IN Operator? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements

✍: FYIcenter.com

A

A subquery can be used with the IN operator as "expression IN (subquery)". The subquery should return a single column with one or more rows to form a list of values to be used by the IN operation. The following tutorial exercise shows you how to use a subquery with the IN operator:

SQL> SELECT first_name, last_name FROM employees 
  2  WHERE department_id IN (
  3    SELECT department_id FROM departments 
  4    WHERE location_id = 1700
  5  );

FIRST_NAME           LAST_NAME
-------------------- -------------------------
Steven               King
Neena                Kochhar
Lex                  De Haan
Nancy                Greenberg
Daniel               Faviet
John                 Chen
Ismael               Sciarra
......

2007-04-19, 5005👍, 0💬

How To Name Query Output Columns
How To Name Query Output Columns? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements Each column in the query output has a default name. If you don't like the default name, you can specify a new name for any column in the query output by using the AS clause. The following statement shows y... 2007-04-19, 5525👍, 0💬

How To Count Groups Returned with the GROUP BY Clause
How To Count Groups Returned with the GROUP BY Clause? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you use the COUNT(*) function on groups returned with the GROUP BY clause, it will count the number of rows within each group, not the number of groups. If you want to count the num... 2007-04-19, 5519👍, 0💬

How To Write a Left Outer Join with the WHERE Clause
How To Write a Left Outer Join with the WHERE Clause? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements 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(+)".... 2007-04-19, 5453👍, 0💬

How To Write an Inner Join with the WHERE Clause
How To Write an Inner Join with the WHERE Clause? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements 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.depar... 2007-04-19, 5304👍, 0💬

How To Write a Query with a Full Outer Join
How To Write a Query with a Full Outer Join? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements 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 ... 2007-04-19, 5238👍, 0💬

What Is a Subquery
What Is a Subquery? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements A subquery is a SELECT statement used as part of the selection criteria of the main SELECT statement. The subquery specified in the WHERE clause will be evaluated repeated on each row of the selection base table. The ou... 2007-04-19, 5141👍, 0💬

How To Use Subqueries with the EXISTS Operator
How To Use Subqueries with the EXISTS Operator? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements A subquery can be used with the EXISTS operator as "EXISTS (subquery)", which returns true if the subquery returns one or more rows. The following statement is a good example of "EXISTS (subq... 2007-04-19, 5123👍, 0💬

How To Use Subqueries with the IN Operator
How To Use Subqueries with the IN Operator? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements A subquery can be used with the IN operator as "expression IN (subquery)". The subquery should return a single column with one or more rows to form a list of values to be used by the IN operation... 2007-04-19, 5006👍, 0💬

What Is a Transaction
What Is a Transaction? - Oracle DBA FAQ - Understanding SQL Transaction Management A transaction is a logical unit of work requested by a user to be applied to the database objects. Oracle server introduces the transaction concept to allow users to group one or more SQL statements into a single tran... 2007-04-18, 5004👍, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.