SQL Server Update statement usage

 

The update statement is used to create an update query and change the Field Values in the specified table based on the specified conditions. The update statement does not generate a result set, and you cannot cancel this operation after updating the query update records.

Syntax: Update table set newvalue where criteria

Description: The table parameter specifies the table name, which contains the data to be changed.
Newvalue is an expression used to calculate the value of a specific field in the update record to be inserted.
The criteria parameter is an expression used to specify the updated record. Only records that match the expression are updated.

Name

Update-replace the column/field values in the table

Syntax

UPDATE table SET col = expression [, ...]    [ FROM fromlist ]    [ WHERE condition ]

Input

Table

Name of an existing table.

Column

Name of the column/field in the table.

Expression

Assign a valid value or expression to a column or field.

Fromlist

Postgres is a non-standard extension that allows columns/fields in other tables to appear in the where condition.

Condition

See the SELECT statement to obtain a further description of the WHERE clause.

Output

Update #

The returned information is successful. # indicates the number of updated rows. If # is equal to 0, no row is updated.

Description

Update changes the declared column/Field Values of all rows that meet the condition. Only the columns/fields to be modified need to appear in the statement.

Array references use the same syntax as select. That is to say, a single array element, a range of array elements, or the entire array can be updated using a query statement.

To change a table, you must have the write permission on it. You must also have the read permission on any table mentioned in the where condition.

Usage

Replace the word "drama" in the field kind with "dramatic:

UPDATE films SET kind = 'Dramatic' WHERE kind = 'Drama';SELECT * FROM films WHERE kind = 'Dramatic' OR kind = 'Drama'; code  |     title     | did | date_prod  |   kind   | len-------+---------------+-----+------------+----------+------- BL101 | The Third Man | 101 | 1949-12-23 | Dramatic | 01:44 P_302 | Becket        | 103 | 1964-02-03 | Dramatic | 02:28 M_401 | War and Peace | 104 | 1967-02-12 | Dramatic | 05:57 T_601 | Yojimbo       | 106 | 1961-06-16 | Dramatic | 01:50 DA101 | Das Boot      | 110 | 1981-11-11 | Dramatic | 02:29

Compatibility sql92

Sql92 defines some different syntaxes in the update statement:

UPDATE table SET column = expression [, ...]    WHERE CURRENT OF cursor

Cursor indicates an open cursor.