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(string-index substring string) ISLISP: returns nil: List.findIndex (List.isPrefixOf substring) (List.tails string) Haskell (returns only index) returns Nothing Str.search_forward (Str.regexp_string substring) string 0: OCaml: raises Not_found Substring.size (#1 (Substring.position substring (Substring.full string))) Standard ML: returns string ...
This is an important element of SQL. Statements, which may have a persistent effect on schemata and data, or may control transactions, program flow, connections, sessions, or diagnostics. SQL statements also include the semicolon (";") statement terminator. Though not required on every platform, it is defined as a standard part of the SQL grammar.
New scalar operations such as string concatenation and substring extraction, date and time mathematics, and conditional statements. New set operations such as UNION JOIN, NATURAL JOIN, set differences, and set intersections. Conditional expressions with CASE. For an example, see Case (SQL). Support for alterations of schema definitions via ...
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.
In relational databases, a condition (or predicate) in a query is said to be sargable if the DBMS engine can take advantage of an index to speed up the execution of the query.
Multiple statements or multi queries must be executed with mysqli_multi_query(). The individual statements of the statement string are separated by semicolon. Then, all result sets returned by the executed statements must be fetched. The MySQL server allows having statements that do return result sets and statements that do not return result ...
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
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.