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mysql经典语句.docx

发布:2018-05-19约3.49千字共7页下载文档
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一查询数值型数据:/article/71341.htm?1SELECT * FROM tb_name WHERE sum 100;?查询谓词:,=,,,!=,!,!,=,=二查询字符串/article/71341.htm?1234SELECT * FROM tb_stu WHERE sname = 小刘SELECT * FROM tb_stu WHERE sname like 刘%SELECT * FROM tb_stu WHERE sname like %程序员SELECT * FROM tb_stu WHERE sname like %PHP%三查询日期型数据/article/71341.htm?1SELECT * FROM tb_stu WHERE date = 2011-04-08?注:不同数据库对日期型数据存在差异: /article/71341.htm?123456(1)MySQL:SELECT * from tb_name WHERE birthday = 2011-04-08??(2)SQL Server:SELECT * from tb_name WHERE birthday = 2011-04-08?????(3)Access:SELECT * from tb_name WHERE birthday = #2011-04-08#四查询逻辑型数据/article/71341.htm?12SELECT * FROM tb_name WHERE type = TSELECT * FROM tb_name WHERE type = F?逻辑运算符:and or not五查询非空数据/article/71341.htm?1SELECT * FROM tb_name WHERE address order by addtime desc?注:相当于PHP中的!=六利用变量查询数值型数据/article/71341.htm?1SELECT * FROM tb_name WHERE id = $_POST[text]注:利用变量查询数据时,传入SQL的变量不必用引号括起来,因为PHP中的字符串与数值型数据进行连接时,程序会自动将数值型数据转变成字符串,然后与要连接的字符串进行连接七利用变量查询字符串数据 /article/71341.htm?1SELECT * FROM tb_name WHERE name LIKE %$_POST[name]%完全匹配的方法%%表示可以出现在任何位置八查询前n条记录/article/71341.htm?1SELECT * FROM tb_name LIMIT 0,$N;?limit语句与其他语句,如order by等语句联合使用,会使用SQL语句千变万化,使程序非常灵活九查询后n条记录/article/71341.htm?1SELECT * FROM tb_stu ORDER BY id ASC LIMIT $n十查询从指定位置开始的n条记录/article/71341.htm?1SELECT * FROM tb_stu ORDER BY id ASC LIMIT $_POST[begin],$n?注意:数据的id是从0开始的十一查询统计结果中的前n条记录/article/71341.htm?1SELECT * ,(yw+sx+wy) AS total FROM tb_score ORDER BY (yw+sx+wy) DESC LIMIT 0,$num十二查询指定时间段的数据?SELECT? 要查找的字段 FROM 表名 WHERE 字段名 BETWEEN 初始值 AND 终止值/article/71341.htm?1SELECT * FROM tb_stu WHERE age BETWEEN 0 AND 18十三按月查询统计数据/article/71341.htm?1SELECT * FROM tb_stu WHERE month(date) = $_POST[date] ORDER BY date ;?注:SQL语言中提供了如下函数,利用这些函数可以很方便地实现按年、月、日进行查询?year(data):返回data表达式中的公元年分所对应的数值?month(data):返回data表达式中的月分所对应的数值?day(data):返回data表达式中的日期所对应的数值十四查询大于指定条件的记录/article/71341.htm?1SELECT * FROM tb_stu WHERE age$_POST[age] ORDER BY age;十五查询结果不显示重复记录?SELECT DISTINCT 字段名 FROM 表名 WHERE 查询条件注:SQL语句中的DISTINCT必
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