Question

将数据从行转换为列。我有两行ID和一行文本VARCHAR2类型的行。但是ID行之一并不总是相同。有时会丢失数据。

我尝试使用PIVOT和GROUP BY，直到现在这只给了我错误。

SELECT prj_id, udn_id, txt_value
FROM TBL
GROUP BY tbl.prj_id;

我想转换一下：（空行仅用于更好的可见性）

PRJ_ID  UDN_ID  TXT_ VALUE
8344    82      13/10/2009
8344    64      E S
8344    178     End

8364    82      12/10/2009
8364    64      A M
8364    89      M
8364    178     Internal

8335    82      05/10/2009
8335    64      E S
8335    89      N
8335    178     End

8377    82      13/10/2009
8377    64      Z D
8377    89      N;M
8377    178     Internal

对此：

        82          64      89      178         
8344    13/10/2009  E S     N/A     End
8364    12/10/2009  A M     M       Internal
8335    05/10/2009  E S     N       End
8377    13/10/2009  Z D     N;M     Internal

有什么想法可以用SQL解决吗？

Answer 1

老式方式（在PIVOT之前）是使用DECODE（或CASE来汇总价值，以提高可读性）。这是一个示例（您正在寻找的第16行）：

SQL> with tbl (prj_id, udn_id, txt_value) as
  2    (select 8344, 82, '13/10/2009' from dual union all
  3     select 8344, 64, 'E S'        from dual union all
  4     select 8344, 178, 'End'       from dual union all
  5     --
  6     select 8364, 82, '12/10/2009' from dual union all
  7     select 8364, 64, 'A M'        from dual union all
  8     select 8364, 89, 'M'          from dual union all
  9     select 8364, 178, 'Internal'  from dual union all
 10     --
 11     select 8335, 82, '05/10/2009' from dual union all
 12     select 8335, 64, 'E S'        from dual union all
 13     select 8335, 89, 'N'          from dual union all
 14     select 8335, 178, 'End'       from dual
 15    )
 16  select prj_id,
 17         max(case when udn_id =  82 then txt_value end) "82",
 18         max(case when udn_id =  64 then txt_Value end) "64",
 19         max(case when udn_id =  89 then txt_value end) "89",
 20         max(case when udn_id = 178 then txt_Value end) "178"
 21  from tbl
 22  group by prj_id;

    PRJ_ID 82         64         89         178
---------- ---------- ---------- ---------- ----------
      8335 05/10/2009 E S        N          End
      8344 13/10/2009 E S                   End
      8364 12/10/2009 A M        M          Internal

SQL>

Answer 2

我是Oracle语法的新手。因此，我用SQL Server语法编写了代码。希望这对您有帮助：

CREATE TABLE Project(PRJ_ID int, UDN_ID INT, TXT_VALUE varchar(100));

INSERT INTO Project VALUES (8344,82,'E S'),(8344,69,'A M'),(8364,82,'End'),(8364,59,'Internal');

DECLARE @columns NVARCHAR(MAX), @columns1 NVARCHAR(MAX), @sql NVARCHAR(MAX);

--selecting distinct values and concatenating to get a result like [82],[69],[82]...


SELECT @columns1 = STUFF((
            SELECT DISTINCT ',' + '['+ CAST(UDN_ID AS VARCHAR) + ']' FROM Project
            FOR XML PATH('')
            ), 1, 1, '')
FROM Project;


--using that dynamic column string in the pivot query string


SET @sql = 'SELECT PRJ_ID,' + @columns1 + ' FROM
(
  SELECT * FROM Project
) AS src
PIVOT
(
  MAX(TXT_VALUE) FOR src.UDN_ID IN ('+ @columns1
  + ')
) AS p;';


--executing the pivot query


EXEC sp_executesql @sql;

Answer 3

使用oracle中的PIVOT可以实现。请在下面使用，如有任何疑问，请通知我。

select * from (
with all_data as(
select '8344' prj_id, 82 id, '40099' txt_val from dual union all
select '8344' prj_id, 64 id, 'E S' txt_val from dual union all
select '8344' prj_id, 178 id, 'End' txt_val from dual union all
select '8364' prj_id, 82 id, '40098' txt_val from dual union all
select '8364' prj_id, 64 id, 'A M' txt_val from dual union all
select '8364' prj_id, 89 id, 'M' txt_val from dual union all
select '8364' prj_id, 178 id, 'Internal' txt_val from dual union all
select '8335' prj_id, 82 id, '40091' txt_val from dual union all
select '8335' prj_id, 64 id, 'E S' txt_val from dual union all
select '8335' prj_id, 89 id, 'N' txt_val from dual union all
select '8335' prj_id, 178 id, 'End' txt_val from dual union all
select '8377' prj_id, 82 id, '40099' txt_val from dual union all
select '8377' prj_id, 64 id, 'Z D' txt_val from dual union all
select '8377' prj_id, 89 id, 'N;M' txt_val from dual union all
select '8377' prj_id, 178 id, 'Internal' txt_val from dual)
select prj_id,id,txt_val from all_data)
pivot
(max(txt_val) 
for id in (82 as "82_val", 64 as "64_val", 89 as "89_val", 178 as "178_val"))
order by 1
;

有时缺少数据时的行到列

3 个答案: