SELECT YourColumn, COUNT(*) TotalCount FROM YourTable GROUP BY YourColumn HAVING COUNT(*) > 1 ORDER BY COUNT(*) DESC http://blog.sqlauthority.com/2007/07/11/sql-server-count-duplicate-records-rows/…

There can be two types of duplication of rows in a table 1. Entire row getting duplicated because there is no primary key or unique key. 2. Only primary key or unique key value is different, but remaining all values are same. Scenario 1: Delete dupli…

oralce中使用 count 函数判断 行数 需要注意 一定是count 有值的字段,接下来看一组语句 --查询数据 select * from kk_create_ka where auto_id='D7313B4716AD4062B82D3CD8513DA7A8'; --count select count(I_E_Flag) from kk_create_ka where auto_id='D7313B4716AD4062B82D3CD8513DA7A8'; select count(*…

Appendices Published: April 27, 2005 On This Page Appendix A: SQL Server for Oracle Professionals Appendix B: Getting the Best Out of SQL Server 2000 and Windows Appendix C: Baselining Appendix D: Installing Common Drivers and Applications Installing…

https://blogs.msdn.microsoft.com/sqlcat/2009/09/11/looking-deeper-into-sql-server-using-minidumps/ Author: Thomas Kejser Reviewers and Contributors: Bob Ward, Michael Thomassy, Juergen Thomas, Hermann Daeubler, Mark Souza, Lubor Kollar, Henk van der…

注意MYSQL使用注释 -- 时 要后面加上空格 使用 #不用 一.数据类型 MYSQL:支持enum和set类型 ;SQL SERVER:不支持 MYSQL:不支持nchar,nvarchar,ntext类型 具体可看 SELECT * FROM msdb.dbo.sysdatatypemappings --SQL SERVER ? DATA TYPES #MYSQL MYSQL:递增语句是AUTO_INCREMENT; SQL SERVER:IDENTITY(1,1) -- MYSQL CR…

我们都知道数据在存储引擎中是以页的形式组织的,但数据页在不同的组织形式中其中对应的数据行存储是不尽相同的,这里通过实例为大家介绍下堆表的中特有的一种情形Forwared Records及处理方式. 概念 堆表中,当对其中的记录进行更新时,如果当前数据页无法满足更新行的容量,此时这行记录将会转移到新的数据页中,而原数据页中将会留下指针(文件号,页号,槽号)链接到新的数据页中. Code 创建测试数据 create database testpage go use testpage go creat…

SQL Server loop - how do I loop through a set of records By using T-SQL and cursors like this : DECLARE @MyCursor CURSOR; DECLARE @MyField YourFieldDataType; BEGIN SET @MyCursor = CURSOR FOR YourField from dbo.table OPEN @MyCursor FETCH NEXT FROM @My…

几乎每次我展示SQL Server里的窗口时,人们都非常有兴趣知道,当你定义你的窗口(指定的一组行)时,ROWS与RANGE选项之间的区别.因此在今天的文章里我想给你展示下这些选项的区别,对于你的分析计算意味着什么. ROWS与RANGE之间的区别 当你用OVER()子句进行你的分析计算来打开你的窗口,你也可以在窗口里看到的,通过ROWS与RANGE选项来限制你的行数.来看下面的T-SQL语句: SELECT t.OrderYear, t.OrderMonth, t.TotalDue, SUM(…

This is a by-design behavior. There is only one allocation unit in tempdb that istracking the versioned records across the server. Cleanup of this allocationunit is decided by the oldest transaction of READ_COMMITTED_SNAPSHOT enableddatabase.  SQL Se…