demo012.sql

来自「T-SQL示例大全」· SQL 代码 · 共 19 行

/*
假设我们替数据表employee的Id、Name与Birthday等三个字段的组合建立一个索引，
则下列各个查询皆属于涵盖式查询：
*/

SELECT Id FROM employee

SELECT Id FROM employee WHERE Id LIKE  'M%'

SELECT Id FROM employee WHERE Name LIKE '许%'

SELECT Id, Name,Birthday FROM employee

SELECT Id, Name,Birthday FROM employee
  WHERE Id LIKE 'M%' AND
                Name LIKE '许%' AND
                Birthday BETWEEN '1973/1/1' AND '1973/12/31'