SQL语言教程,入门经典 使用Transact-SQL语句修改表 语法格式: ALTER TABLE table_name { [ALTER COLUMN column_name { new_data_type [(precision [, scale])] [NULL|NOT NULL] | {ADD|DROP} ROWGUIDCOL } ] | ADD { [ ] | column_name AS computed_column_expression }[ , ... n ] | [ WITH CHECK | WITH NO