Friday, November 13, 2009

UPDATE Statement Syntax

Modify existing rows with the UPDATE statement :
  • UPDATE table SET column = value [, column = value, ...] [WHERE condition];
  • Update more than one row at a time (if required).
Updating Rows in a Table :

Specific row or rows are modified if you specify the WHERE clause :
  • UPDATE emp SET deptno = 40 WHERE empno = 7654;
All rows in the table are modified if you omit the WHERE clause :
  • UPDATE copy_emp SET deptno = 110;
Updating Two Columns with a Subquery :

  • Update employee 7654’s job and sal to match that of employee 7698
UPDATE emp SET job = (SELECT job FROM emp WHERE empno = 7698), sal = (SELECT sal FROM emp WHERE empno = 7698) WHERE empno = 7654;

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