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mapper.xml 中共用
mapper.xml 间共用
项目中也许我们会遇到一段sql语句被多个查询、增加等语句用到的情况，如何去偷懒呢，复用sql无疑是较好的选择
这里只提供简单的示范：
如果只是单表查询，并且希望共用的sql只会出现在同一个mapper.xml文件中，那么我们可以直接在
<mapper namespace="XXXXX"></mapper></div>
中写下面的业务代码
<sql id="unitSql">
a.userId,a.legalCode,legalName,
bidderCodeType,legalRole,
licenseNo,DATE_FORMAT(licenseEndDate,"%Y-%m-%d") AS licenseEndDate,
taxCertNo,DATE_FORMAT(taxCertEndDate,"%Y-%m-%d") AS taxCertEndDate,
localTaxCertNo,DATE_FORMAT(localTaxCertEndDate,"%Y-%m-%d") AS localTaxCertEndDate,
organNo,DATE_FORMAT(organCertEndDate,"%Y-%m-%d") AS organCertEndDate,
legalRepresent,legalType,
perresentPhone,legalIndustary,creditRate,
countryRegion,legalUnitAddress,regionCode,registerProvince,
a.regCapital,a.regCapCurRency,a.regUnit,
registerCity,registerCounty,basicBank,basicBranchBank,
basicAccountNo,basicAccountName,legalContact,legalContactPhone,
legalContactAddress,legalWeb,legalZipCode,legalEmail,
legalStatus
</sql>
</div>
然后引用
<select id="getTenderAgentById" parameterType="String" resultType="Map">
select <include refid="unitSql"/>, -- 就是这句话引用 ，refid为共有sql语句id
b.auditOpinion,b.createUser,
b.createTime,
b.lastUpdateUser,
b.lastUpdateTime,
b.disabled,b.infoStatus
from P_legalUnit a, P_tenderAgent b
where b.userId=#{userId} AND a.userId = b.userId AND b.disabled='0'
</select>
</div>
如果是连表查询，那么我们极有可能会希望有一个sql语句被多个mapper.xml引用的的方法，很简单。
我们可以新建一个mapper.xml文件（当然，这个mapper.xml要在你的扫描路径下，本文不赘述）。取名为common.xml
该文件内容为
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="common">
<sql id="common.unitSql">
a.userId,a.legalCode,legalName,
bidderCodeType,legalRole,
licenseNo,DATE_FORMAT(licenseEndDate,"%Y-%m-%d") AS licenseEndDate,
taxCertNo,DATE_FORMAT(taxCertEndDate,"%Y-%m-%d") AS taxCertEndDate,
localTaxCertNo,DATE_FORMAT(localTaxCertEndDate,"%Y-%m-%d") AS localTaxCertEndDate,
organNo,DATE_FORMAT(organCertEndDate,"%Y-%m-%d") AS organCertEndDate,
legalRepresent,legalType,
perresentPhone,legalIndustary,creditRate,
countryRegion,legalUnitAddress,regionCode,registerProvince,
a.regCapital,a.regCapCurRency,a.regUnit,
registerCity,registerCounty,basicBank,basicBranchBank,
basicAccountNo,basicAccountName,legalContact,legalContactPhone,
legalContactAddress,legalWeb,legalZipCode,legalEmail,
legalStatus
</sql>
</mappper>
</div>
在另一个mapper.xml文件引用
<select id="getTenderAgentById" parameterType="String" resultType="Map">
select <include refid="common.unitSql"/>, -- 就是这句话引用 ，refid为共有sql语句id
b.auditOpinion,b.createUser,
b.createTime,
b.lastUpdateUser,
b.lastUpdateTime,
b.disabled,b.infoStatus
from P_legalUnit a, P_tenderAgent b
where b.userId=#{userId} AND a.userId = b.userId AND b.disabled='0'
</select>
</div>
==注:为何我的文件名要取为common.xml并且id也为common.unitSql呢？这是为了后期维护方便，如此，可以更容易找到该共有的sql在哪一个文件==
以上所述是小编给大家介绍的Mybatis中 SQL语句复用，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
</div>