mybatis and,or復(fù)合查詢操作

更新時(shí)間：2020年11月27日 15:03:42 作者：cuyun11

這篇文章主要介紹了mybatis and,or復(fù)合查詢操作，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。一起跟隨小編過來看看吧

要查詢的sql:

select * from user where name = ? and (age=? or city=?)；

方法1：不使用Example查詢

直接在usermapper.xml中修改sql

方法2：使用Example查詢

sql可轉(zhuǎn)換成

select * from user where (name = ? and age=?) or (name=? and city=?)；

然后使用Example查詢

UserExample example=new UserExample();
example.or().orAgeLike("%"+searchParam+"%").andNameEqualTo(userName);
example.or().orCityLike("%"+searchParam+"%").andNameEqualTo(userName);

補(bǔ)充知識(shí)：MySQL/Mybatis多個(gè)AND和OR混用注意事項(xiàng)

mysql中AND的優(yōu)先級(jí)高于OR，所以在查詢時(shí)，會(huì)優(yōu)先執(zhí)行AND條件，除非使用（）來將一個(gè)AND和OR括起來，這樣才能使得OR得以按照語句的順序執(zhí)行。

如下圖所示：

java測(cè)試代碼

@Test
 public void TestMutil(){
  Species species = new Species();
  ArrayList<String> arrayList = new ArrayList<String>();
  arrayList.add("長(zhǎng)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文件中沒有使用（）放在語句中執(zhí)行情況

<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（）放在語句中執(zhí)行情況

<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>

補(bǔ)充：

如果這里使用多個(gè)%來解決上述的含有多個(gè)OR和AND情況，那么所實(shí)現(xiàn)功能會(huì)有問題，因?yàn)槎鄠€(gè)關(guān)鍵詞有%來連接，會(huì)有一個(gè)次序問題。具體效果見下圖