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A derived table is the use of referencing an SQL subquery in a FROM clause. Essentially, the derived table is a subquery that can be selected from or joined to. The derived table functionality allows the user to reference the subquery as a table. The derived table is sometimes referred to as an inline view or a subselect.
A list may contain the same value more than once, and each occurrence is considered a distinct item. A singly-linked list structure, implementing a list with three integer elements. The term list is also used for several concrete data structures that can be used to implement abstract lists, especially linked lists and arrays.
MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [6] is an open-source relational database management system (RDBMS). [6] [7] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [1] and "SQL", the acronym for Structured Query Language.
SELECT list is the list of columns or SQL expressions to be returned by the query. This is approximately the relational algebra projection operation. AS optionally provides an alias for each column or expression in the SELECT list. This is the relational algebra rename operation. FROM specifies from which table to get the data. [3]
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]
The simplest form of index is a sorted list of values that can be searched using a binary search with an adjacent reference to the location of the entry, analogous to the index in the back of a book. The same data can have multiple indexes (an employee database could be indexed by last name and hire date). Indexes affect performance, but not ...
Unlike function and class names, variable names are case-sensitive. Both double-quoted ("") and heredoc strings allow the ability to embed a variable's value into the string. [13] As in C, variables may be cast to a specific type by prefixing the type in parentheses. PHP treats newlines as whitespace, in the manner of a free-form language.
SQLite: A VIEW named "dual" that works the same as the Oracle "dual" table can be created as follows: CREATE VIEW dual AS SELECT 'x' AS dummy; SAP HANA has a table called DUMMY that works the same as the Oracle "dual" table. Teradata database does not require a dummy table. Queries like 'select 1 + 1' can be run without a "from" clause/table name.