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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. As SQL is a declarative programming language, SELECT queries specify a result set, but do not specify how to calculate it.
Cardinality (SQL statements) In SQL (Structured Query Language), the term cardinality refers to the uniqueness of data values contained in a particular column (attribute) of a database table. The lower the cardinality, the more duplicated elements in a column. Thus, a column with the lowest possible cardinality would have the same value for ...
PostgreSQL, MySQL and Oracle support natural joins; Microsoft T-SQL and IBM DB2 do not. The columns used in the join are implicit so the join code does not show which columns are expected, and a change in column names may change the results. In the SQL:2011 standard, natural joins are part of the optional F401, "Extended joined table", package.
A query includes a list of columns to include in the final result, normally immediately following the SELECT keyword. An asterisk ("*") can be used to specify that the query should return all columns of the queried tables. SELECT is the most complex statement in SQL, with optional keywords and clauses that include:
A relational database (RDB[1]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [2] A database management system used to maintain relational databases is a relational database management system (RDBMS). Many relational database systems are equipped with the option of using SQL (Structured Query Language ...
MySQL (/ ˌmaɪˌɛsˌkjuːˈɛl /) [ 5 ] is an open-source relational database management system (RDBMS). [ 5 ][ 6 ] Its name is a combination of "My", the name of co-founder Michael Widenius 's daughter My, [ 7 ] and "SQL", the initialism for Structured Query Language.
Outline of MySQL. The following outline is provided as an overview of and topical guide to MySQL: MySQL ("My Structured Query Language ") – world's second most [ a] widely used relational database management system (RDBMS) [ 3] and most widely used open-source RDBMS. [ 4] It is named after co-founder Michael Widenius 's daughter, My.
MySQL Workbench is a visual database design tool that integrates SQL development, administration, database design, creation and maintenance into a single integrated development environment for the MySQL database system. It is the successor to DBDesigner 4 from fabFORCE.net, and replaces the previous package of software, MySQL GUI Tools Bundle.