Home
SQL programmingYou can use the HCL OneDB™ implementation of the SQL language to develop applications for HCL OneDB™ database servers.
Guide to SQL: SyntaxThe HCL OneDB™ Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the HCL OneDB™ dialect of the SQL language.
SQL statementsThis chapter describes the syntax and semantics of SQL statements that are recognized by HCL OneDB™.
UPDATE statementUse the UPDATE statement to change the values in one or more columns of one or more existing rows in a table or view.
SET ClauseUse the SET clause to identify the columns to be updated and assign values to each column.
Using a Subquery to Update a Single Column

Using a Subquery to Update a Single Column

You can update the column specified in the SET clause with the value that a subquery returns.

UPDATE orders
   SET ship_charge =
      (SELECT SUM(total_price) * .07 FROM items
         WHERE orders.order_num = items.order_num)
   WHERE orders.order_num = 1001;

If you are updating a supertable in a table hierarchy, the SET clause cannot include a subquery that references a subtable. If you are updating a subtable in a table hierarchy, a subquery in the SET clause can reference the supertable if it references only the supertable. That is, the subquery must use the SELECT ...; FROM ONLY (supertable) syntax.