开发中遇到的问题---使用mybatis时 有一个sql查询不到结果 日志也显示查询为o 但是从日志中取出执行的sql到数据库客户端手动执行，可以查到数据

Posted 2021-03-05 少年攻城狮

问题：使用mybatis时 有一个sql查询不到结果 日志也显示查询为o 但是从日志中取出执行的sql到数据库客户端手动执行，可以查到数据；

原因：MyBatis看到 #{}会认为你在给sql中的变量赋值，就像JDBC编程中给问号赋值一样(自动在前后加单引号)也就是说，他把你传入的字符串并没有当做多个值，而是当做一个大的字符串，所以查询不到值

而MyBatis看到${}的时候会直接将之替换成变量的值而不做任何处理；

解决方案：将查询条件中的“#”替换成“$”。

<select id="findAllToExcel" parameterType="com.aspire.sms2019.model.dto.ProductQueryCondition"
          resultType="map">
    SELECT
    cp.ID id,
    cp.`NAME` `name`,
    cp.`STATUS` `status`,
    cp.CREATE_BY createBy,
    DATE_FORMAT(cp.CREATE_TIME,‘%Y-%m-%d %H:%i:%s‘) createTime,
    cp.UPDATE_BY updateBy,
    DATE_FORMAT(cp.UPDATE_TIME,‘%Y-%m-%d %H:%i:%s‘) updateTime,
    c1.`NAME` cmppName,
    c4.`NAME` cmppName1,
    c5.`NAME` cmppName2,
    cp.CHANNEL_CMPP_USED cmppNameUsed,
    GROUP_CONCAT(distinct concat(c13.`NAME`,‘:‘, case cpr1.STATUS when 0 THEN ‘无效‘ ELSE ‘有效‘end )
    ORDER BY cpr1.PRIORITY desc) cmppPriorityName,
    c2.`NAME` sgipName,
    c7.`NAME` sgipName1,
    c8.`NAME` sgipName2,
    cp.CHANNEL_SGIP_USED sgipNameUsed,
    GROUP_CONCAT(distinct concat(c14.`NAME`,‘:‘, case cpr2.STATUS when 0 THEN ‘无效‘ ELSE ‘有效‘end )
    ORDER BY cpr2.PRIORITY desc) sgipPriorityName,
    c3.`NAME` smgpName,
    c10.`NAME` smgpName1,
    c11.`NAME` smgpName2,
    cp.CHANNEL_SMGP_USED smgpNameUsed,
    GROUP_CONCAT(distinct concat(c15.`NAME`,‘:‘, case cpr3.STATUS when 0 THEN ‘无效‘ ELSE ‘有效‘end )
    ORDER BY cpr3.PRIORITY desc) smgpPriorityName
    FROM
    channel_product cp
    LEFT OUTER JOIN channel c1 ON cp.CHANNEL_CMPP_ID = c1.id
    LEFT OUTER JOIN channel c4 ON cp.CHANNEL_CMPP_ID1 = c4.id
    LEFT OUTER JOIN channel c5 ON cp.CHANNEL_CMPP_ID2 = c5.id
    LEFT OUTER JOIN channel c2 ON cp.CHANNEL_SGIP_ID = c2.id
    LEFT OUTER JOIN channel c7 ON cp.CHANNEL_SGIP_ID1 = c7.id
    LEFT OUTER JOIN channel c8 ON cp.CHANNEL_SGIP_ID2 = c8.id
    LEFT OUTER JOIN channel c3 ON cp.CHANNEL_SMGP_ID = c3.id
    LEFT OUTER JOIN channel c10 ON cp.CHANNEL_SMGP_ID1 = c10.id
    LEFT OUTER JOIN channel c11 ON cp.CHANNEL_SMGP_ID2 = c11.id
    left outer join channel_priority cpr1 on (cpr1.PRODUCT_ID = cp.ID and cpr1.CHANNEL_TYPE=0)
    left outer join channel c13 on (cpr1.CHANNEL_ID =c13.ID and cpr1.CHANNEL_TYPE = 0)
    left outer join channel_priority cpr2 on (cpr2.PRODUCT_ID = cp.ID and cpr2.CHANNEL_TYPE=1)
    left outer join channel c14 on (cpr2.CHANNEL_ID =c14.ID and cpr2.CHANNEL_TYPE = 1)
    left outer join channel_priority cpr3 on (cpr3.PRODUCT_ID = cp.ID and cpr3.CHANNEL_TYPE=2)
    left outer join channel c15 on (cpr3.CHANNEL_ID =c15.ID and cpr3.CHANNEL_TYPE = 2)
    <where>
      <if test="productName != null and productName != ‘‘">
        AND cp.NAME like CONCAT(‘%‘,${productName},‘%‘)
      </if>
      <if test="status != null">
        AND cp.STATUS = #{status}
      </if>
    </where>
    GROUP BY cp.ID
    ORDER BY cp.ID DESC
  </select>