UPDATE

The UPDATE statement changes values in rows that already exist. The WHERE clause decides which rows change - and forgetting it changes every row in the table.

UPDATE syntax

• Basic shape: UPDATE table SET column = value WHERE condition.
• SET can change several columns at once, separated by commas.
• The new value can be a literal, a host variable, NULL, or an expression like SALARY * 1.10.
• Always check SQLCODE after UPDATE, then COMMIT to make the change permanent.

Why WHERE matters

• Without WHERE, UPDATE changes every row in the table. This is the most common beginner disaster.
• Safe habit: run the same condition as a SELECT first and count the rows.
• In SPUFI and interactive tools, some shops block UPDATE without WHERE completely.
• For wide updates, commit in batches so locks are not held too long.

Example

• Giving a 10 percent raise to one department:-