An SQL UPDATE statement changes the data of one or more records in a table. Either all the rows can be updated, or a subset may be chosen using a condition.
For the UPDATE
to be successful, the user must have data manipulation privileges (UPDATE
privilege) on the table or column, the updated value must not conflict with all the applicable constraints (such as primary keys, unique indexes, CHECK
constraints, and NOT NULL
constraints).
Set the value of column C1 in table T1 to 2, only if the value of column C2 is found in the sub list of values in column C3 in table T2 having the column C4 equal to 0.
The SQL:2003 standard does not support updates of a joined table. Therefore, the following method needs to be used. Note that the subselect in the SET clause must be a scalar subselect, i.e. it can return at most a single row.