mybatis and,or复合查询操作
作者：cuyun11
这篇文章主要介绍了mybatis and,or复合查询操作，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧
要查询的sql:
select * from user where name = ? and (age=? or city=?)；
方法1：不使用Example查询
直接在usermapper.xml中修改sql
方法2：使用Example查询
sql可转换成
select * from user where (name = ? and age=?) or (name=? and city=?)；
然后使用Example查询
UserExample example=new UserExample();
example.or().orAgeLike("%"+searchParam+"%").andNameEqualTo(userName);
example.or().orCityLike("%"+searchParam+"%").andNameEqualTo(userName);
补充知识：MySQL/Mybatis多个AND和OR混用注意事项
mysql中AND的优先级高于OR，所以在查询时，会优先执行AND条件，除非使用（）来将一个AND和OR括起来，这样才能使得OR得以按照语句的顺序执行。
如下图所示：
java测试代码
@Test
public void TestMutil(){
Species species = new Species();
ArrayList<String> arrayList = new ArrayList<String>();
arrayList.add("长喙蚤");
arrayList.add("尤氏");
List<Species> querySpeciesesListByMutilCondition = this.speciesMapper.querySpeciesesListByMutilCondition(arrayList, species.getEnglishName(), species.getHost(), species.getPosition(), species.getLocation(), species.getPhylum(), species.getClassName(), species.getOrder(), species.getFamily(), species.getJenus());
for (Species s : querySpeciesesListByMutilCondition) {
System.out.println(s);
}
System.out.println(querySpeciesesListByMutilCondition.size());
}
Mapper文件中没有使用（）放在语句中执行情况
<select id="querySpeciesesListByMutilCondition" resultType="Species">
SELECT * FROM t_json_species
<where>
<if test="englisName != null and englisName != ''">AND englishName like CONCAT('%',#{englishName},'%') OR sameName like CONCAT('%',#{englishName},'%')</if>
<if test="host != null and host != ''">AND host like CONCAT('%',#{host},'%')</if>
<if test="position != null and position != ''">AND position like CONCAT('%',#{position},'%')</if>
<if test="location != null and location != ''">AND location like CONCAT('%',#{location},'%')</if>
<if test="phylumName != null and phylumName != ''">AND phylumName = #{phylumName}</if>
<if test="className != null and className != ''">AND className = #{className}</if>
<if test="orderName != null and orderName != ''">AND orderName = #{orderName}</if>
<if test="familyName != null and familyName != ''">AND familyName = #{familyName}</if>
<if test="jenusName != null and jenusName != ''">AND jenusName = #{jenusName}</if>
<if test="nameList != null and nameList != ''">
<foreach collection="nameList" item="name" >AND name like CONCAT('%',#{name},'%') OR sameName like CONCAT('%',#{name},'%')</foreach>
</if>
</where>
</select>
Mapper文件中使用（）放在语句中执行情况
<select id="querySpeciesesListByMutilCondition" resultType="Species">
SELECT * FROM t_json_species
<where>
<if test="englisName != null and englisName != ''">AND englishName like CONCAT('%',#{englishName},'%') OR sameName like CONCAT('%',#{englishName},'%')</if>
<if test="host != null and host != ''">AND host like CONCAT('%',#{host},'%')</if>
<if test="position != null and position != ''">AND position like CONCAT('%',#{position},'%')</if>
<if test="location != null and location != ''">AND location like CONCAT('%',#{location},'%')</if>
<if test="phylumName != null and phylumName != ''">AND phylumName = #{phylumName}</if>
<if test="className != null and className != ''">AND className = #{className}</if>
<if test="orderName != null and orderName != ''">AND orderName = #{orderName}</if>
<if test="familyName != null and familyName != ''">AND familyName = #{familyName}</if>
<if test="jenusName != null and jenusName != ''">AND jenusName = #{jenusName}</if>
<if test="nameList != null and nameList != ''">
<foreach collection="nameList" item="name" >AND (name like CONCAT('%',#{name},'%') OR sameName like CONCAT('%',#{name},'%'))</foreach>
</if>
</where>
</select>
补充：
如果这里使用多个%来解决上述的含有多个OR和AND情况，那么所实现功能会有问题，因为多个关键词有%来连接，会有一个次序问题。具体效果见下图
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