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SQL-92
Guide and Reference
Query Expressions
A query expression selects the specified column values from one or more rows contained in one or more tables specified in the FROM clause. The selection of rows is restricted by a search condition in the WHERE clause. The temporary table derived through the clauses of a select statement is called a result table.
Query expressions form the basis of other SQL statements and syntax elements:
- SELECT statements are query expressions with optional ORDER BY and FOR UPDATE clauses.
- INSERT statements can specify a query expression to add the rows of the result table to a table.
- UPDATE statements can specify a query expression that returns a single row to modify columns of a row.
- Some search conditions can specify query expressions. In basic predicates, the result table can contain only a single value. In a quantified_predicate and an in_predicate, the result table can contain only a single column.
- The FROM clause of a query expression can specify another query expression, called a derived table.
This is the syntax for a query_expression:
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