{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"背景介绍"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"笔者在工作中曾遇到SyBase数据库迁移至MySQL时的一个问题：使用bcp将SyBase中的数据导出为csv文件时，datetime数据类型默认导出格式与MySQL不兼容。Sybase默认的datetime类型格式为Mmm dd yyyy hh:nn:ss:sssAA，示例如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"Dec 24 2017 12:00:00:000PM\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"而MySQL中datetime类型格式为yyyy-mm-dd hh:nn:ss，示例如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"2017-12-24 12:00:00"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"因此直接将csv文件导入MySQL会由于不兼容导致报错。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"解决方式"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"解决此问题的方式不外乎两种：一是修改导出后的csv文件，令其时间字段的数据格式兼容MySQL；二是修改SyBase数据库中时间字段的数据格式，使其直接能通过bcp导出兼容MySQL的csv文件。鉴于第一种方法较为复杂，本文笔者采用第二种方法解决该问题。"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"1、convert()函数介绍"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"convert()函数是SyBase数据库中用于数据类型转换的函数，其使用方式如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"convert(datatype,expression,[format-style])"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"datatype：必选参数，将要转换成的数据类型；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"expression：必选参数，待转换的字段；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"format-style：可选参数，转换时间类型时，决定输出格式的参数，对应关系见下表："}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"embedcomp","attrs":{"type":"table","data":{"content":"format-style的值 输出格式 输出示例 100 Mmm dd yyyy hh:nnAA Dec 24 2017 12:00PM 101 mm\/dd\/yyyy 12\/24\/2017 102 yyyy.mm.dd 2017.12.24 103 dd\/mm\/yyyy 24\/12\/2017 104 dd.mm.yyyy 24.12.2017 105 dd-mm-yyyy 24-12-2017 106 dd Mmm yyyy 24 Dec 2017 107 Mmm dd,yyyy Dec 24,2017 108 hh:nn:ss 12:00:00 109 Mmm dd yyyy hh:nn:ss:sssAA Dec 24 2017 12:00:00:000PM 110 mm-dd-yyyy 12-24-2017 111 yyyy\/mm\/dd 2017\/12\/24 112 yyyymmdd 20171224"}}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"例如有一个名为test的表，将该表中一个名为changetime，类型为datetime的字段转换为varchar类型，可以使用如下SQL语句："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"\nselect convert(varchar(100),changetime,111) as dates from test;"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"若该字段仅有一行数据，其值为Dec 24 2017 12:00:00:000PM，那么以上SQL输出的结果为2017\/12\/24."}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"2、str_replace()函数介绍"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"str_replace()参数用于替换字符串中的部分字符，其使用方式如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"str_replace(‘string1’,’string2’,’string3’)"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"参数含义："}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"string1：必选参数，原始字符串；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"string2：必选参数，待转换的字符；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"string3：必选参数，需要转换成的字符；"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"例如以下SQL："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"select str_replace(‘2017\/12\/24’,’\/’,’-’);"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"其输出结果为2017-12-24."}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"3、具体方案实施"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"由以上示例可见，若将SyBase中datetime类型字段使用convert()函数转换为varchar类型，format-style的值指定为111，再使用str_replace()函数，将convert()转换来的字符串中的’\/’转换为’-’，即可满足MySQL中对datetime类型的格式要求（yyyy-mm-dd）；同理，format-style的值指定为108，即可满足hh:nn:ss的格式要求。具体的实施方案举例说明如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1）在SyBase数据库建立一张临时表tmp，表结构与待导出数据的表test一致，仅datetime类型字段改为varchar类型；表结构见以下SQL语句："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"create table test(id int,time datetime);\ncreate table tmp(id int,time varchar(100));"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2）采用如下SQL语句将原始表的数据存入临时表中："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"insert into tmp select id,str_replace(convert(varchar(100),time,111),'\/','-')\n+' '+convert(varchar(100),time,108) from test;"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"3）将临时表tmp中的数据使用bcp命令导出为csv文件；"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"4）将csv文件中的数据导入MySQL数据库对应表中。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"至此，解决了SyBase中datetime类型字段默认导出格式与MySQL不兼容的问题。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"作者介绍"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"农行研发中心“数风云”团队，"},{"type":"text","text":"一支朝气蓬勃、快速成长的技术团队，始终致力于农行大数据、数据库和云计算等领域的应用实践与技术创新，探索数据赋能，勇攀数据云巅，为企业数字化转型和金融科技发展不断贡献力量。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文转载自：dbaplus社群（ID：dbaplus）"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"原文链接："},{"type":"link","attrs":{"href":"https:\/\/mp.weixin.qq.com\/s\/HsoFd9vtWTCQYElcRvdT8Q","title":"xxx","type":null},"content":[{"type":"text","text":"银行数据库迁移至MySQL，竟被时间字段这玩意耍了……"}]}]}]} 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