mysql连接两张表，得到匹配记录中非零值的字段名

标签 mysql sql join query-optimization mariadb

我得到了如下两个表格

mysql> show tables;
+-------------------+
| Tables_in_testdbs |
+-------------------+
| dts               |
| ref               |
+-------------------+
2 rows in set (0.00 sec)

各表内容如下

mysql> select * from ref;
+----+------+------+
| Id | key1 | key2 |
+----+------+------+
|  1 |    1 |    1 |
|  2 |    1 |    2 |
|  3 |    2 |    2 |
|  4 |    3 |    1 |
|  5 |    3 |    2 |
|  6 |    3 |    3 |
+----+------+------+
6 rows in set (0.00 sec)

mysql> select * from dts;
+----+------+------+--------+------+------+------+------+------+
| Id | key1 | key2 | serial | pr1  | pr2  | pr3  | pr4  | pr5  |
+----+------+------+--------+------+------+------+------+------+
|  1 |    1 |    1 |      1 |    0 |    0 |    1 |    0 |    2 |
|  2 |    1 |    1 |      2 |    0 |    0 |    0 |    0 |    0 |
|  3 |    1 |    1 |      3 |    0 |    0 |    0 |    1 |    0 |
|  4 |    1 |    1 |      4 |    1 |    0 |    1 |    1 |    3 |
|  5 |    1 |    2 |      5 |    0 |    0 |    0 |    2 |    5 |
|  6 |    1 |    2 |      6 |    0 |    0 |    0 |    0 |    1 |
|  7 |    1 |    2 |      7 |    0 |    1 |    0 |    0 |    0 |
|  8 |    2 |    2 |      1 |    1 |    1 |    1 |    1 |    2 |
|  9 |    2 |    2 |      2 |    0 |    0 |    0 |    0 |    0 |
| 10 |    3 |    2 |      3 |    0 |    0 |    0 |    0 |    0 |
| 11 |    3 |    3 |      1 |    1 |    1 |    0 |    0 |    1 |
| 12 |    3 |    3 |      5 |    0 |    0 |    1 |    1 |    0 |
+----+------+------+--------+------+------+------+------+------+
12 rows in set (0.00 sec)

这是我尝试连接两个表的方法

mysql> select distinct
    ->        i.key1,
    ->        i.key2 
    -> from 
    ->        ref i, 
    ->        dts d 
    -> where 
    ->        i.key1=d.key1 and 
    ->        i.key2=d.key2 ;
+------+------+
| key1 | key2 |
+------+------+
|    1 |    1 |
|    1 |    2 |
|    2 |    2 |
|    3 |    2 |
|    3 |    3 |
+------+------+
5 rows in set (0.00 sec)

我期待低于o/p，真的不知道如何得到它

key1       key2 fields_non_zero
1           1   pr1,pr3,pr4,pr5
1           2   pr2,pr4,pr5
2           2   pr1,pr2,pr3,pr4,pr5
3           2
3           3   pr1,pr2,pr3,pr4,pr5

例如，我想使用以下条件进行检查，让匹配的两个表的 key1=1 和 key2=1

  1. Join two table
  2. check is there any non zero data in fields(pr1-pr5) of dts, which is matched
  3. If found concat field name with comma,
  4. suppose if all fields are non zero, just concat fields and stop joining further for same key1, key2 because if found all (save execution time), go to next key1,key2
+----+------+------+
| Id | key1 | key2 |
+----+------+------+
|  1 |    1 |    1 |              <- for ref table key1,key2 following rows matches 

| Id | key1 | key2 | serial | pr1  | pr2  | pr3  | pr4  | pr5  |  nonzero_fields 
+----+------+------+--------+------+------+------+------+------+
|  1 |    1 |    1 |      1 |    0 |    0 |    1 |    0 |    2 |  = pr3,pr5
|  2 |    1 |    1 |      2 |    0 |    0 |    0 |    0 |    0 |  =  
|  3 |    1 |    1 |      3 |    0 |    0 |    0 |    1 |    0 |  = pr4
|  4 |    1 |    1 |      4 |    1 |    0 |    1 |    1 |    3 |  = pr1,pr3,pr4,p45

  So distinct of below are

         = pr3,pr5
         = 
         = pr4
         = pr1,pr3,pr4,p45 

 key1   key2 fields_non_zero
 1       1   pr1,pr3,pr4,pr5

我至少不介意如果我没有像下面这样的订单

 key1   key2 fields_non_zero
 1       1   pr3,pr5,pr4,pr1

表结构如下

DROP TABLE IF EXISTS `dts`;
CREATE TABLE `dts` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `key1` int(11) DEFAULT '-99',
  `key2` int(11) DEFAULT '-99',
  `serial` int(11) DEFAULT '-99',
  `pr1` int(11) DEFAULT '-99',
  `pr2` int(11) DEFAULT '-99',
  `pr3` int(11) DEFAULT '-99',
  `pr4` int(11) DEFAULT '-99',
  `pr5` int(11) DEFAULT '-99',
  PRIMARY KEY (`Id`),
  KEY `main` (`key1`,`key2`,`serial`)
) ENGINE=MyISAM AUTO_INCREMENT=13 DEFAULT CHARSET=latin1;


LOCK TABLES `dts` WRITE;
INSERT INTO `dts` VALUES (1,1,1,1,0,0,1,0,2),(2,1,1,2,0,0,0,0,0),(3,1,1,3,0,0,0,1,0),(4,1,1,4,1,0,1,1,3),(5,1,2,5,0,0,0,2,5),(6,1,2,6,0,0,0,0,1),(7,1,2,7,0,1,0,0,0),(8,2,2,1,1,1,1,1,2),(9,2,2,2,0,0,0,0,0),(10,3,2,3,0,0,0,0,0),(11,3,3,1,1,1,0,0,1),(12,3,3,5,0,0,1,1,0);
UNLOCK TABLES;



DROP TABLE IF EXISTS `ref`;
CREATE TABLE `ref` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `key1` int(11) DEFAULT '-99',
  `key2` int(11) DEFAULT '-99',
  PRIMARY KEY (`Id`),
  KEY `main` (`key1`,`key2`)
) ENGINE=MyISAM AUTO_INCREMENT=7 DEFAULT CHARSET=latin1;


LOCK TABLES `ref` WRITE;
INSERT INTO `ref` VALUES (1,1,1),(2,1,2),(3,2,2),(4,3,1),(5,3,2),(6,3,3);
UNLOCK TABLES;

最佳答案

您可以从 dts 表中反透视数据，然后对其使用 group_concat。

SELECT 
    r.key1,
    r.key2,
    group_concat(distinct case when val > 0 then pr end order by pr separator ',') prs
FROM
    ref r
        INNER JOIN
    (
    SELECT
    d.key1,
    d.key2,
    t.pr,
    CASE t.pr
        WHEN 'pr1' THEN pr1
        WHEN 'pr2' THEN pr2
        WHEN 'pr3' THEN pr3
        WHEN 'pr4' THEN pr4
        WHEN 'pr5' THEN pr5
    END val
FROM
    dts d
        CROSS JOIN
    (
    SELECT 'pr1' pr UNION ALL 
    SELECT 'pr2' UNION ALL 
    SELECT 'pr3' UNION ALL 
    SELECT 'pr4' UNION ALL 
    SELECT 'pr5') t
    ) d ON r.key1 = d.key1 AND r.key2 = d.key2
GROUP BY r.key1 , r.key2;

产生:

+------+------+---------------------+
| key1 | key2 | prs                 |
+------+------+---------------------+
|    1 |    1 | pr1,pr3,pr4,pr5     |
|    1 |    2 | pr2,pr4,pr5         |
|    2 |    2 | pr1,pr2,pr3,pr4,pr5 |
|    3 |    2 | NULL                |
|    3 |    3 | pr1,pr2,pr3,pr4,pr5 |
+------+------+---------------------+
5 rows in set (0.00 sec)

编辑:

没有加入 ref 表(因为 ref 表有所有的 key1，key2，我们只是在内部加入它):

SELECT 
    key1,
    key2,
    group_concat(distinct case when val > 0 then pr end order by pr separator ',') prs
FROM (
    SELECT 
        d.key1,
            d.key2,
            t.pr,
            CASE t.pr
                WHEN 'pr1' THEN pr1
                WHEN 'pr2' THEN pr2
                WHEN 'pr3' THEN pr3
                WHEN 'pr4' THEN pr4
                WHEN 'pr5' THEN pr5
            END val
    FROM
        dts d
    CROSS JOIN (
        SELECT 'pr1' pr UNION ALL 
        SELECT 'pr2' UNION ALL 
        SELECT 'pr3' UNION ALL 
        SELECT 'pr4' UNION ALL 
        SELECT 'pr5'
    ) t
) r
GROUP BY key1 , key2;

产生相同的输出:

+------+------+---------------------+
| key1 | key2 | prs                 |
+------+------+---------------------+
|    1 |    1 | pr1,pr3,pr4,pr5     |
|    1 |    2 | pr2,pr4,pr5         |
|    2 |    2 | pr1,pr2,pr3,pr4,pr5 |
|    3 |    2 | NULL                |
|    3 |    3 | pr1,pr2,pr3,pr4,pr5 |
+------+------+---------------------+
5 rows in set (0.00 sec)

编辑 2:

SELECT 
    r.key1,
    r.key2,
    group_concat(distinct case when val > 0 then pr end order by pr separator ',') prs
FROM (
    select key1, key2
    from ref
    order by id
    limit 0, 1000       -- Added limit to get only first 1000 key pairs based on id
) r INNER JOIN (
    SELECT
    d.key1,
    d.key2,
    t.pr,
    CASE t.pr
        WHEN 'pr1' THEN pr1
        WHEN 'pr2' THEN pr2
        WHEN 'pr3' THEN pr3
        WHEN 'pr4' THEN pr4
        WHEN 'pr5' THEN pr5
    END val
FROM
    dts d
        CROSS JOIN
    (
    SELECT 'pr1' pr UNION ALL 
    SELECT 'pr2' UNION ALL 
    SELECT 'pr3' UNION ALL 
    SELECT 'pr4' UNION ALL 
    SELECT 'pr5') t
    ) d ON r.key1 = d.key1 AND r.key2 = d.key2
GROUP BY r.key1 , r.key2;

对于前 1000 个唯一 key 对，在上面的查询中使用以下 SQL:

(
    select key1, key2
    from ref
    group by key1, key2
    order by key1, key2
    limit 0, 1000       -- Added limit to get only first 1000 key pairs based on id
) r

关于mysql连接两张表，得到匹配记录中非零值的字段名，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41856497/

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