我正在尝试将行转置为列,按唯一标识符 (CASE_ID) 分组。
我有一张这样结构的桌子:
CASE_ID AMOUNT TYPE
100 10 A
100 50 B
100 75 A
200 33 B
200 10 C
我正在尝试查询它以生成此结构...
| CASE_ID | AMOUNT1 | TYPE1 | AMOUNT2 | TYPE2 | AMOUNT3 | TYPE3 |
|---------|---------|-------|---------|-------|---------|--------|
| 100 | 10 | A | 50 | B | 75 | A |
| 200 | 33 | B | 10 | C | (null) | (null) |
(假设具有大量 CASE_ID、TYPE 和 AMOUNT 可能值的更大数据集)
我尝试使用数据透视表,但我不需要聚合函数(只是尝试重组数据)。现在我正在尝试以某种方式使用
row_number
但不确定如何使用。
我基本上是在尝试复制和调用 Casestovars 的 SPSS 命令,但需要能够在 SQL 中完成。谢谢。
您可以通过使用
row_number()
创建一个序列号然后使用带有CASE表达式的聚合函数来获得结果:
select case_id,
max(case when seq = 1 then amount end) amount1,
max(case when seq = 1 then type end) type1,
max(case when seq = 2 then amount end) amount2,
max(case when seq = 2 then type end) type2,
max(case when seq = 3 then amount end) amount3,
max(case when seq = 3 then type end) type3
from
(
select case_id, amount, type,
row_number() over(partition by case_id
order by case_id) seq
from yourtable
) d
group by case_id;
如果您使用的是具有 PIVOT 功能的数据库产品,那么您可以将
row_number()
与 PIVOT 一起使用,但首先我建议您先取消旋转 amount
和 type
列。 SQL Server 中有限数量的值的基本语法是:
select case_id, amount1, type1, amount2, type2, amount3, type3
from
(
select case_id, col+cast(seq as varchar(10)) as col, value
from
(
select case_id, amount, type,
row_number() over(partition by case_id
order by case_id) seq
from yourtable
) d
cross apply
(
select 'amount', cast(amount as varchar(20)) union all
select 'type', type
) c (col, value)
) src
pivot
(
max(value)
for col in (amount1, type1, amount2, type2, amount3, type3)
) piv;
如果您有未知数量的值,那么您可以使用动态 SQL 来获取结果 - SQL Server 语法为:
DECLARE @cols AS NVARCHAR(MAX),
@query AS NVARCHAR(MAX)
select @cols = STUFF((SELECT ',' + QUOTENAME(col+cast(seq as varchar(10)))
from
(
select row_number() over(partition by case_id
order by case_id) seq
from yourtable
) d
cross apply
(
select 'amount', 1 union all
select 'type', 2
) c (col, so)
group by col, so
order by seq, so
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set @query = 'SELECT case_id,' + @cols + '
from
(
select case_id, col+cast(seq as varchar(10)) as col, value
from
(
select case_id, amount, type,
row_number() over(partition by case_id
order by case_id) seq
from yourtable
) d
cross apply
(
select ''amount'', cast(amount as varchar(20)) union all
select ''type'', type
) c (col, value)
) x
pivot
(
max(value)
for col in (' + @cols + ')
) p '
execute sp_executesql @query;
参见 SQL Fiddle with Demo。每个版本都会给出结果:
| CASE_ID | AMOUNT1 | TYPE1 | AMOUNT2 | TYPE2 | AMOUNT3 | TYPE3 |
|---------|---------|-------|---------|-------|---------|--------|
| 100 | 10 | A | 50 | B | 75 | A |
| 200 | 33 | B | 10 | C | (null) | (null) |
以下是大查询的解决方案:
DECLARE cols STRING;
DECLARE query STRING;
SET cols = (
SELECT STRING_AGG(DISTINCT CONCAT(column, CAST(seq AS STRING)), ',')
FROM (
SELECT column, ROW_NUMBER() OVER(PARTITION BY case_id ORDER BY case_id) AS seq
FROM yourtable
CROSS JOIN UNNEST(['amount', 'type']) AS column
)
);
SET query = (
SELECT CONCAT(
'SELECT case_id, ', cols, ' ',
'FROM (',
' SELECT case_id, CONCAT(column, CAST(seq AS STRING)) AS column, value ',
' FROM (',
' SELECT case_id, amount, type, ',
' ROW_NUMBER() OVER(PARTITION BY case_id ORDER BY case_id) AS seq ',
' FROM yourtable',
' ) ',
' CROSS JOIN UNNEST(["amount", "type"]) AS column ',
' CROSS JOIN (',
' SELECT "amount" AS column, CAST(amount AS STRING) AS value FROM yourtable UNION ALL ',
' SELECT "type" AS column, type AS value FROM yourtable ',
' ) ',
' WHERE column = CONCAT(column, CAST(seq AS STRING))',
') ',
'PIVOT(MAX(value) FOR column IN (', cols, '))'
)
);
EXECUTE IMMEDIATE query;