<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[qq_44802002的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/qq_44802002</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; qq_44802002]]></copyright><item><title><![CDATA[一次sqlserver查询调优]]></title><link>https://blog.youkuaiyun.com/qq_44802002/article/details/131228373</link><guid>https://blog.youkuaiyun.com/qq_44802002/article/details/131228373</guid><author>qq_44802002</author><pubDate>Thu, 15 Jun 2023 15:24:19 +0800</pubDate><description><![CDATA[最开始以为是分页+order by 的问题，因为原始语句写了order by ，业务系统中传进来的语句是加了分页处理，仔细测试后发现和order by 无关，根本原因在查询的字段类型是text格式。text格式不走索引所以导致特别慢。有中文就用nvarchar(n)，n 个字节的可变长度且非 Unicode 的字符数据，字段长度varchar的8000是字节数，一个英文占一个字节，一个汉字占两个字节。DATALENGTH返回的字节，对应excel的是LENB，LEN是字符，对应excel里的是len。]]></description><category></category></item><item><title><![CDATA[SQLSERVER CDC相关]]></title><link>https://blog.youkuaiyun.com/qq_44802002/article/details/126739894</link><guid>https://blog.youkuaiyun.com/qq_44802002/article/details/126739894</guid><author>qq_44802002</author><pubDate>Wed, 07 Sep 2022 10:14:00 +0800</pubDate><description><![CDATA[CDC SQLSERVER]]></description><category></category></item><item><title><![CDATA[SQLSERVER连oracle]]></title><link>https://blog.youkuaiyun.com/qq_44802002/article/details/125766862</link><guid>https://blog.youkuaiyun.com/qq_44802002/article/details/125766862</guid><author>qq_44802002</author><pubDate>Wed, 13 Jul 2022 16:26:35 +0800</pubDate><description><![CDATA[SQLSERVER连oracle]]></description><category></category></item><item><title><![CDATA[2021-07-30]]></title><link>https://blog.youkuaiyun.com/qq_44802002/article/details/119246599</link><guid>https://blog.youkuaiyun.com/qq_44802002/article/details/119246599</guid><author>qq_44802002</author><pubDate>Fri, 30 Jul 2021 14:16:44 +0800</pubDate><description><![CDATA[sql2005版本有个函数ISNUMERIC(expression)函数：当expression为数字时，返回1，否则返回0。


select ISNUMERIC('123') --结果为1

但是，该函数有个缺点！

SELECT
,ISNUMERIC('-') as '-'  --1
,ISNUMERIC('+') as '+'  --1
,ISNUMERIC('$') as '$'  --1
,ISNUMERIC('.') as '.'  --1
,ISNUMERIC(',...]]></description><category></category></item></channel></rss>