Order By

An ORDER BY clause in

SQL Structured Query Language (SQL) (pronounced ''S-Q-L''; or alternatively as "sequel") is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling s ...

specifies that a SQL SELECT statement returns a

result set A result set is the set of results returned by a query, usually in the same format as the database the query is called on. For example, in SQL, which is used in conjunction with relational databases, it is the result of a SELECT query on a table ...

with the rows being sorted by the values of one or more columns. The sort criteria does not have to be included in the result set (restrictions apply for SELECT DISTINCT, GROUP BY,

UNION  ISTINCT/code>, EXCEPT  ISTINCT/code> and INTERSECT  ISTINCT/code>.) The sort criteria can be expressions, including column names,  user-defined functions, arithmetic operations, or CASE expressions.  The expressions are evaluated and the results are used for the sorting, i.e., the values stored in the column or the results of the function call.

ORDER BY is the ''only'' way to sort the rows in the result set.  Without this clause, the relational database system 





In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users,  applications, and the database itself to capture and anal ...
 may return the rows in any order.  If an ordering is required, the ORDER BY must be provided in the SELECT statement sent by the application.  Although some database systems allow the specification of an ORDER BY clause in subqueries or  view definitions, the presence there has no effect on the final result-set order, but makes sense when combined with a result offset clause or a fetch first clause.  A view is a logical relational table, and the relational model 
The relational model (RM) is an approach to managing data using a structure and language consistent with  first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd, where all data are represented in terms of t ...
 mandates that a table is a set of rows, implying no sort order whatsoever.  The only exception are constructs like ORDER BY ORDER OF ... (not standardized in  SQL:2003) which allow the propagation of sort criteria through nested subqueries.

The SQL standard's core functionality does not explicitly define a default sort order for Null 
Null may refer to:

 Science, technology, and mathematics Astronomy
*Nuller, an optical tool using interferometry to block certain sources of light Computing
*Null (SQL) (or NULL), a special marker and keyword in SQL indicating that a data value do ...
s. With the  SQL:2003 extension T611, "Elementary OLAP operations", nulls can be sorted before or after all data values by using the NULLS FIRST or NULLS LAST clauses of the ORDER BY list, respectively. Not all DBMS vendors implement this functionality, however.  Vendors who do not implement this functionality may specify different treatments for Null sorting in the DBMS.

Structure ORDER BY ... DESC will order in descending order, otherwise ascending order is used. (The latter may be specified explicitly using ASC.)

  Examples 



SELECT * FROM Employees 
ORDER BY LastName, FirstName

This sorts by the LastName column, then by the FirstName column if LastName matches.

  References 






 SQL keywords
 Articles with example SQL code



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