随笔分类 -  数据库

数据库
SQL SERVER – Difference between COUNT(DISTINCT) vs COUNT(ALL)
摘要：http://blog.sqlauthority.com/2011/03/08/sql-server-difference-between-countdistinct-vs-countall/COUNT(DISTINCT)和COUNT(ALL)的区别：前者像select distinct 字段1,字段2 from table一样会去掉重复的，后者则是统计字段的所有数据条数，与Count(字段1)相同。COUNT(ALL)中的ALL实际上是缺省项，不需要指定。(注：本人还有点怀疑COUNT(ALL)与COUNT(字段1)是否有区别，待验证)。Here is the script:1 SELECT 阅读全文
posted @ 2011-03-09 22:35 Net205 Blog 阅读(518) 评论(0) 推荐(0)
SQL Performance
摘要：SQL Azure Performance – Query Optimization:http://www.sqlazureperformance.com/2010/sql-azure-performance-query-optimization/Simple Query tuning with STATISTICS IO and Execution plans:http://www.simple-talk.com/sql/performance/simple-query-tuning-with-statistics-io-and-execution-plans/显示图形执行计划 (SQL S 阅读全文
posted @ 2011-03-09 21:25 Net205 Blog 阅读(160) 评论(0) 推荐(0)
MSSQL删除重复数据
摘要：DECLARE @table TABLE(gd varchar(100), [time] datetime)INSERT INTO @table SELECT 'gd550765', '2009-08-14 16:02:07.293'UNION ALL SELECT 'gd550765', '2009-08-14 16:19:41.000'UNION ALL SELECT 'gd550765', ... 阅读全文
posted @ 2009-08-16 23:54 Net205 Blog 阅读(1984) 评论(1) 推荐(1)
Web网站栏目转Wap网站栏目(工作代码)
该文被密码保护。
posted @ 2009-04-03 18:16 Net205 Blog 阅读(6) 评论(0) 推荐(0)
MSSQL相关应用收集
摘要：在查找问题的时候，无意搜索到这个Blog：http://blogs.x2line.com，发现有好一些内容不错，实际项目完全有可能用到，特收集起来1、SQL Tip: HowTo Convert Delimited String to TableMany times we need to deal with lists in T-SQL, for instance we need to have ... 阅读全文
posted @ 2009-01-13 12:13 Net205 Blog 阅读(493) 评论(0) 推荐(0)