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all rows for which the predicate in the WHERE clause is True are affected (or returned) by the SQL DML statement or query. Rows for which the predicate evaluates to False or Unknown are unaffected by the DML statement or query. The following query returns only those rows from table mytable where the value in column mycol is greater than 100.
Using an INSERT statement with RETURNING clause for PostgreSQL (since 8.2). The returned list is identical to the result of a INSERT . Firebird has the same syntax in Data Modification Language statements (DSQL); the statement may add at most one row. [ 2 ]
Queries allow the user to describe desired data, leaving the database management system (DBMS) to carry out planning, optimizing, and performing the physical operations necessary to produce that result as it chooses. A query includes a list of columns to include in the final result, normally immediately following the SELECT keyword.
In database management systems (DBMS), a prepared statement, parameterized statement, (not to be confused with parameterized query) is a feature where the database pre-compiles SQL code and stores the results, separating it from data. Benefits of prepared statements are: [1]
The MySQL database supports prepared statements. A prepared statement or a parameterized statement is used to execute the same statement repeatedly with high efficiency. Basic workflow. The prepared statement execution consists of two stages: prepare and execute. At the prepare stage a statement template is sent to the database server.
There is also an IGNORE clause for the INSERT statement, [7] which tells the server to ignore "duplicate key" errors and go on (existing rows will not be inserted or updated, but all new rows will be inserted). SQLite's INSERT OR REPLACE INTO works similarly. It also supports REPLACE INTO as an alias for compatibility with MySQL. [8]
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).
SQL table row (INSERT INTO statement) IDL operation declaration IO field definition Cell of SQL table row in INSERT INTO statement (cell value) Portion of IDL operation declaration, typically related to declaration of an operation type code, parameter list, operation return value, or list of exceptions