SQL data Modification Statement

The statement used in the SQL language to modify data in a relational table in a database is update, which can be used to modify the values of one or more columns in a selected row in a relational table, using the following format:

Updata < table name >

Set column name = Expression,..., Column name = Expression

[where< search term;]

The search conditions in the WHERE clause are also allowed to contain another SELECT query statement.

Example 10: To the current no quota of sales staff assigned 6000 yuan quota.

Updata Salesreps

SET quota=6000

WHERE QUOTA is NULL

Example 11: A salesperson who accepts a total order over 9000 yuan after January 1, 1999 reports directly to John (number 104).

UPDATE Salesreps

SET manager=104

WHERE 9000< (SELECT SUM (AMOUNT)

From ORDERS WHERE order_date> "01-01-99"

References: SQL language tutorials SQL language basics

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