SQL pivot table 分层格式的查询和连接查询

Question

Table-1

Resource    Rank1   Rank2   Rank3   Rank4
Critical    3         3         6    12
High        8         8        12     24

Table-2

Name     Issue      SLC   
RAM     Critical    Rank1   
KIRAN   Critical    Rank2
BASS    High        Rank3
LOUT    Critical    Rank4
chinna  High        Rank1
lavanya Critical    Rank3
babau   High        Rank4
rani    Critical    Rank2

预计应该

Name    Issue       SLC   values RESOURCEMISS
RAM     Critical    Rank1   3      Resource 
KIRAN   Critical    Rank2   3      Resource 
BASS    High        Rank3  12      Resource 
LOUT    Critical    Rank4  12       Resource    
chinna  High        Rank1  8      Resource  
lavanya Critical    Rank3   6      Resource 
babau   High        Rank4  24    Resource   
rani    Critical    Rank2  3     Resource

这不应该像 [RESOURCEMISS]='Resoure'

Answer 1

认为你可以尝试这样的事情：

SELECT 
    Name
    Issue
    SLC
    Values.value
FROM
    Table-2
LEFT JOIN
    (
        SELECT 'Rank1' descrip, Rank1 value FROM Table-1
        UNION ALL
        SELECT 'Rank2' descrip, Rank1 value FROM Table-1
        UNION ALL
        SELECT 'Rank3' descrip, Rank1 value FROM Table-1
        UNION ALL
        SELECT 'Rank4' descrip, Rank1 value FROM Table-1
    ) as Values
ON Values.descrip = Issue

基于Mysql Convert Column to row (Pivot table )

Answer 2

一个有点难看的解决方案，使用相关子查询来查找每个排名和问题：

SELECT
    Name,
    Issue,
    SLC,
    (SELECT CASE WHEN t2.SLC = 'Rank1' THEN t1.Rank1
                 WHEN t2.SLC = 'Rank2' THEN t1.Rank2
                 WHEN t2.SLC = 'Rank3' THEN t1.Rank3
                 WHEN t2.SLC = 'Rank4' THEN t1.Rank4 END
     FROM table1 t1
     WHERE t1.Resource = t2.Issue) "values"
FROM table2 t2;

Demo

我不知道您实际使用的是什么数据库（MySQL 或 SQL 服务器），但考虑到您当前的设计，这可能并不重要。您的模式未规范化，理想情况下，排名数字应该是某个列中某处的实际值，而不是列名本身。 @strawberry 似乎建议对您的设计进行重构，这使得它更容易进行，只使用一个内部连接。

Answer 3

按照以下几行考虑解决方案（坦率地说，与此明显不同的任何内容都是在浪费您的时间）：

DROP TABLE IF EXISTS table1;

CREATE TABLE table1
(resource VARCHAR(12) NOT NULL
,slc_rank INT NOT NULL
,val INT NOT NULL
,PRIMARY KEY(resource,slc_rank)
);

INSERT INTO table1 VALUES
('Critical',1,3),
('Critical',2,3),
('Critical',3,6),
('Critical',4,12),
('High',1, 8),
('High',2, 8),
('High',3,12),
('High',4,24);

DROP TABLE IF EXISTS table2;

CREATE TABLE table2
(name VARCHAR(20) NOT NULL
,resource VARCHAR(12) NOT NULL
,slc_rank INT NOT NULL
,PRIMARY KEY(name,resource,slc_rank)
);

INSERT INTO table2 VALUES
('RAM','Critical',1),
('KIRAN','Critical',2),
('BASS','High',3),
('LOUT','Critical',4),
('chinna','High',1),
('lavanya','Critical',3),
('babau','High',4),
('rani','Critical',2);

SELECT x.*
     , y.val 
  FROM table2 x 
  JOIN table1 y 
    ON y.resource = x.resource 
   AND y.slc_rank = x.slc_rank;
+---------+----------+----------+-----+
| name    | resource | slc_rank | val |
+---------+----------+----------+-----+
| babau   | High     |        4 |  24 |
| BASS    | High     |        3 |  12 |
| chinna  | High     |        1 |   8 |
| KIRAN   | Critical |        2 |   3 |
| lavanya | Critical |        3 |   6 |
| LOUT    | Critical |        4 |  12 |
| RAM     | Critical |        1 |   3 |
| rani    | Critical |        2 |   3 |
+---------+----------+----------+-----+

SQL pivot table 分层格式的查询和连接查询

SQL pivot table query and hookup query in hierarchical format

tsql

sql-server

sql-server-2014

Demo