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基本常用查询--selectselect * from student; --all 查询所有select all sex from student; --distinct 过滤重复select distinct sex from student; --count 统计select count(*) from student;select count(sex) from student;select count(distinct sex) from student; --top 取前N条记录select top 3 * from student; --alias column name 列重命 阅读全文
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IF EXISTS(SELECT * FROM SYSOBJECTS WHERE NAME = 'StuWebName')DROP TABLE StuWebNameGOCREATE TABLE StuWebName(StuId INT IDENTITY(1,1) PRIMARY KEY,StuName VARCHAR(50) NOT NULL,StuPassword VARCHAR(50) NOT NULL,StuSex CHAR(2) DEFAULT('男'),StuNo INT NOT NULL)GODECLARE @ID INTSET @ID=1WHILE 阅读全文
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//一般情况下我们会这么删除 DataTable dt = new DataTable(); for (int i = 0; i < dt.Rows.Count; i++) { if (99 % i == 0) { dt.Rows.RemoveAt(i); } } //但是这么删除会出现... 阅读全文
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USE SilverlightDemo--SilverlightDemo为你所在的数据库GOselect b.[name] '表名',max(a.rowcnt) '记录数' from sysindexes a join sys.objects b on b.object_id=a.id where b.type='U' group by b.[name] 阅读全文
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首先创建表和添加数据想要的结果--方法一SELECT DISTINCT C.[USER_NAME] AS '姓名',(SELECT SCORE FROM TEST_TB_GRADE WHERE [USER_NAME]=C.[USER_NAME] AND COURSE='语文') AS '语文',(S... 阅读全文