mybatis XML 中 、 、 、 等標簽的使用？多條件查詢該怎么處理？

mybatis XML 中<if>、<choose>、<when>、<otherwise>等標簽的使用

一般使用在多條查詢，雖然也可以通過注解寫，我比較菜，我不會。

一般多條查詢怎么解決？

1.如果是單表間的多條件查詢我是直接調用mybatis plus的api ，里面可以有直接判空條件的api。

如:queryWrapper.like(StringUtils.isNotEmpty(變量參數), "表字段",變量參數);

2.如果是多表間的多條件查詢，我建議用XML來做吧，當然注解也行。

<if>其實跟java的if類似，符合條件的就進去，那符合的進去，不符合的怎么辦呢，

mybatis 提供了<choose>、<when>、<otherwise>這組標簽組合着用，<when>就相當於if，<otherwise>就相當於else，但是<when>、<otherwise>需要放在<choose>里面才能使用。

這邊我就用我最近遇到一個業務來演示吧。一個多表且不同表條件的查詢 如下:

看看我的XML文件<if>、<where>、<choose>、<when>、<otherwise>等標簽一條語句搞定。

建議模糊查詢的參數在傳參就先將參數做個處理，如: “%參數%”，網上也有人直接在XML里寫成這樣 '%'||'#{參數}||'%'，但是這種寫法查出來的數據范圍可能會偏大 。

<?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="cn.mindgd.mapper.MaterielStorageMapper">
    <!--建立查詢的列與對象屬性的對應關系-->
    <!--由於查出來的數據是多張表的，我這邊就在實體類添加了一些渲染字段，下面用給這些字段取了別名-->

    <resultMap id="BaseResultMap" type="cn.mindgd.domain.MaterielStorage">
        <result column="materiel_storage_id" property="materielStorageId"/>
        <result column="material_code" property="materialCode"/>
        <result column="material_name" property="materialName"/>
        <result column="property_name" property="materialTypeName"/>
        <result column="stock" property="stock"/>
        <result column="total" property="total"/>
    </resultMap>

<!--COUNT(1) OVER() mysql 5.7 沒有這個語法OVER() ==>分頁查詢返回總記錄數-->

<select id="findMaterielStorageByMore" resultMap="BaseResultMap"> SELECT ms.materiel_storage_id AS materiel_storage_id,ms.position,m.material_code AS material_code,m.material_name AS material_name,dp.property_name AS property_name,ms.stock AS stock,COUNT(1) OVER() AS total FROM materiel_storage ms LEFT JOIN material m ON m.material_id=ms.material_id LEFT JOIN data_dictionary_property dp ON m.material_type_id=dp.property_id LEFT JOIN warehouse w ON w.warehouse_id=ms.warehouse_id LEFT JOIN construction_team ct ON ct.team_id =ms.team_id WHERE 1=1 
<choose>
            <!-- 集合判空 --> 
            <when test="(null != warehouseIds and warehouseIds.size>0) and (null != teamIds and teamIds.size>0)"> 
                AND (
                w.warehouse_id IN
                <foreach collection="warehouseIds" item="warehouseId" open="(" separator=","
                         close=")">#{warehouseId}
                </foreach>
                OR ct.team_id
                IN
                <foreach collection="teamIds" item="teamId" open="(" separator=","
                         close=")">#{teamId}
                </foreach>
                )
            </when>
            <otherwise>
                <if test="null != warehouseIds and warehouseIds.size>0">
                    AND w.warehouse_id
                    IN
                    <foreach collection="warehouseIds" item="warehouseId" open="(" separator=","
                             close=")">#{warehouseId}
                    </foreach>
                </if>
                <if test="null != teamIds and teamIds.size>0">
                    AND ct.team_id
                    IN
                    <foreach collection="teamIds" item="teamId" open="(" separator=","
                             close=")">#{teamId}
                    </foreach>
                </if>
            </otherwise>
        </choose>
        <!-- 字符串判空 -->
        <if test="null != materialName and '' !=materialName">
            AND m.material_name like #{materialName}
        </if>

        <if test="null != materialCode and '' !=materialCode">
            AND m.material_code=#{materialCode}
        </if>
        <!-- Integer類型判空  如果加了 and '' !=propertyId ,0 就傳不進去了，也就是不能像判斷字符串一樣去判斷他是否是空字符串-->
        <if test="null != propertyId">
            AND dp.property_id=#{propertyId}
        </if>

        <if test="null != teamName and '' !=teamName">
            AND ct.team_name like #{teamName}
        </if>
        <if test="(null != currentPage) and (null != size)">
            LIMIT #{currentPage},#{size}
        </if>
    </select>
</mapper>

 直接在測試類測試

@SpringBootTest
public class TestMaterielStorage {
    @Autowired(required = false)
    MaterielStorageMapper materielStorageMapper;


    @Test
    public void findMaterielStorageByMore() {
        List<Integer> warehouseIds = new ArrayList<>();
        warehouseIds.add(1);
        warehouseIds.add(2);
        List<Integer> teamIds = new ArrayList<>();
//        teamIds.add(1);
//        teamIds.add(2);
        List<MaterielStorage> materielStorageByMore =
//                materielStorageMapper.findMaterielStorageByMore("施", "P", null, 1, warehouseIds, teamIds, 0, 10);
                materielStorageMapper.findMaterielStorageByMore(null, null, null,
                        null, null, null, 0, 10);
        System.out.println("輸出:" + materielStorageByMore);
    }
}

效果1：

效果2：

 

 效果3:

 

 

 

想看更多精彩內容，可以關注我的CSDN

我的CSDN