Name
SELECT
Synopsis
The SELECT
statement retrieves rows, columns, and derived values from one or
many tables of a database.
Vendor |
Command |
---|---|
SQL Server |
Supported, with variations (ANSI joins supported) |
MySQL |
Supported, with variations (ANSI joins partially supported) |
Oracle |
Supported, with variations (ANSI joins not supported) |
PostgreSQL |
Supported, with variations (ANSI joins partially supported) |
SQL99 Syntax and Description
The full syntax of the SELECT
statement is
powerful and complex, but can be broken down into these main clauses:
SELECT [ALL | DISTINCT] select_list FROM table_name1 [,..., table_nameN] [JOIN join_condition] [WHERE search_condition] [GROUP BY group_by_expression] [HAVING search_condition] [ORDER BY order_expression [ASC | DESC] ]
Each clause of the SELECT
statement has a
specific use. Thus, it is possible to speak individually of the
FROM
clause, the WHERE
clause, or the GROUP BY
clause. However, not
every query needs every clause. At a minimum, a query needs a
SELECT
item list and a FROM
clause. (Microsoft SQL Server and PostgreSQL both support certain
types of queries that do not need a FROM
clause.
Refer to the examples below for more information.)
The SELECT item list
The SELECT item list
basically includes all items of information a user wants to retrieve from the server. Different types of elements can appear in the select item list. It’s possible to retrieve literal strings, aggregate functions, and mathematical calculations. In Microsoft SQL ...
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