mysql 同表 父子关系查询 亲测可用

Posted 2021-12-03 一点唐城

一、函数系列：

1、根据传入id查询所有父节点的id

delimiter // 
CREATE FUNCTION `getParList`(rootId INT)
RETURNS varchar(1000) 
BEGIN
    DECLARE sTemp VARCHAR(1000);
    DECLARE sTempPar VARCHAR(1000); 
    SET sTemp = ; 
    SET sTempPar =rootId; 

    #循环递归
    WHILE sTempPar is not null DO 
        #判断是否是第一个，不加的话第一个会为空
        IF sTemp !=  THEN
            SET sTemp = concat(sTemp,,,sTempPar);
        ELSE
            SET sTemp = sTempPar;
        END IF;
        SET sTemp = concat(sTemp,,,sTempPar); 
        SELECT group_concat(pid【父节点ID】) INTO sTempPar FROM 表名 where pid<>id and FIND_IN_SET(id,sTempPar)>0; 
    END WHILE; 

RETURN sTemp; 
END
//

普通查询： select * from treenodes where FIND_IN_SET(id,getParList(15));

mybatis：

<!--根据子id查找其父类别-->
    <select id="getParList" resultMap="BaseResultMap" parameterType="Integer">
        select 
             c.id,c.ad_name,c.ad_parent_code 
        from 
             <include refid="tableName"></include> c 
        where 
             FIND_IN_SET(id,getADParList(#{id})); 
    </select>

2、根据传入id查询所有子节点的id

delimiter // 
CREATE FUNCTION `getChildList`(rootId INT)
RETURNS varchar(1000) 

BEGIN
    DECLARE sTemp VARCHAR(1000);
    DECLARE sTempChd VARCHAR(1000);

    SET sTemp = $;
    SET sTempChd =cast(rootId as CHAR);

    WHILE sTempChd is not null DO
        SET sTemp = concat(sTemp,,,sTempChd);
        SELECT group_concat(id) INTO sTempChd FROM  表名 where FIND_IN_SET(父节点ID,sTempChd)>0;
    END WHILE;
    RETURN sTemp; 
END
//执行命令

普通查询：select * from treenodes where FIND_IN_SET(id,getChildList(7));

mybatis：

<!--根据父类id查找其子类别-->
    <select id="getChildList" resultMap="BaseResultMap" parameterType="Integer">
        select 
             c.id,c.ad_name,c.ad_parent_code 
        from 
            <include refid="tableName"></include> c 
        where 
             FIND_IN_SET(id,getADChildList(#{id})); 
    </select>

二、普通Sql【mybatis】

<!--根据父类id查找其子类别-->
    <select id="getById" resultMap="BaseResultMap" parameterType="Integer">
        SELECT 
                <include refid="Base_Column_List" />
            FROM
                <include refid="tableName"></include>
            WHERE 
                parent_id = #{id}
    </select>

    <!--查找所有类别(递归)-->
    <select id="getAll" resultMap="BaseResultMap" parameterType="Integer">
        SELECT 
                <include refid="Base_Column_List" />
            FROM
                <include refid="tableName"></include>
        WHERE 1 = 1
        <choose>
            <when test="ad_parent_code ==0">
                AND c_bi_admin_division.ad_parent_code IS NULL
            </when>
            <otherwise>
                AND id = #{ad_parent_code}
            </otherwise>
        </choose>
    </select>

三、其他：

1、普通sql查询：

SELECT T2.id,T2.ad_name[ps:字段]
          FROM ( 
              SELECT 
                      @r AS _id, 
                      (SELECT @r := ad_parent_code[ps：父id] FROM 表名 WHERE id = _id) AS ad_parent_code, 
                       @l := @l + 1 AS lvl 
              FROM 
                      (SELECT @r := #{id}, @l := 0) vars, 
                      表名 h 
              WHERE @r <> 0) T1 
        JOIN 表名 T2 
     ON T1._id = T2.id
ORDER BY id;

举个栗子：

SELECT T2.id,T2.uname
          FROM ( 
              SELECT 
                      @r AS _id, 
                      (SELECT @r := parent_id FROM user WHERE id = _id) AS parent_id , 
                       @l := @l + 1 AS lvl 
              FROM 
                      (SELECT @r := #{id}, @l := 0) vars, 
                      user h 
              WHERE @r <> 0) T1 
          JOIN user T2 
    ON T1._id = T2.id
ORDER BY id;

2、mybatis【mapper.xml使用】

<select id="findParentMessageById" parameterType="Integer" resultMap="BaseResultMap">
        <![CDATA[
            SELECT T2.id,T2.uname
                FROM ( 
                    SELECT 
                            @r AS _id, 
                            (SELECT @r := parent_id FROM user WHERE id = _id) AS parent_id , 
                             @l := @l + 1 AS lvl 
                    FROM 
                            (SELECT @r := #{id}, @l := 0) vars, 
                            user h 
                    WHERE @r <> 0) T1 
                JOIN user T2 
        ON T1._id = T2.id
    ORDER BY id;
        ]]>
</select>

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