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The SQL SELECT statement returns a result set of rows, from one or more tables. [1] [2] A SELECT statement retrieves zero or more rows from one or more database tables or database views. In most applications, SELECT is the most commonly used data manipulation language (DML) command.
In SQL, the data manipulation language comprises the SQL-data change statements, [3] which modify stored data but not the schema or database objects. Manipulation of persistent database objects, e.g., tables or stored procedures, via the SQL schema statements, [3] rather than the data stored within them, is considered to be part of a separate data definition language (DDL).
Major DBMSs, including SQLite, [5] MySQL, [6] Oracle, [7] IBM Db2, [8] Microsoft SQL Server [9] and PostgreSQL [10] support prepared statements. Prepared statements are normally executed through a non-SQL binary protocol for efficiency and protection from SQL injection, but with some DBMSs such as MySQL prepared statements are also available using a SQL syntax for debugging purposes.
The derived table is sometimes referred to as an inline view or a subselect. In the following example, the SQL statement involves a join from the initial "Book" table to the derived table "sales". This derived table captures associated book sales information using the ISBN to join to the "Book" table.
As of 21 November 2024 (the day of PHP 8.4's release), PHP is used as the server-side programming language on 75.4% of websites where the language could be determined; PHP 7 is the most used version of the language with 49.1% of websites using PHP being on that version, while 37.9% use PHP 8, 12.9% use PHP 5 and 0.1% use PHP 4. [19]
However, some extensions which use the PHP extension framework do not expose an API to the PHP developer. The PDO MySQL driver extension, for example, does not expose an API to the PHP developer, but provides an interface to the PDO layer above it. MySQLi is an improved version of the older PHP MySQL driver, offering various benefits. [3]
One can use nested stored procedures by executing one stored procedure from within another. Stored procedures may return result sets, i.e., the results of a SELECT statement. Such result sets can be processed using cursors, by other stored procedures, by associating a result-set locator, or by applications. Stored procedures may also contain ...
An ORDER BY clause in SQL specifies that a SQL SELECT statement returns a result set 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 [DISTINCT], EXCEPT [DISTINCT] and INTERSECT [DISTINCT].)