PostgreSQL说“返回和sql元组描述不兼容". [英] PostgreSQL says "return and sql tuple descriptions are incompatible"
问题描述
我有以下数据:
ID CLASS VALUE
1 NHB 700905.7243
1 HBW 164216.1311
1 HBO 700905.7243
2 NHB 146023.3792
2 HBW 89543.2972
2 HBO 82152.072
3 NHB 1409818.328
3 HBW 220430.7922
3 HBO 323512.9391
4 NHB 48711.3814
4 HBW 163385.1575
4 HBO 363352.3441
我想重新组织为:
ID HBO HBW NHB
1 700905.7243 164216.1311 700905.7243
2 82152.072 89543.2972 146023.3792
3 323512.9391 220430.7922 1409818.328
4 363352.3441 163385.1575 48711.3814
请注意,HBW,HBO和NHB列中的值为总计(总和).
Please note that the values in columns HBW, HBO and NHB are totals (sum).
这是我用来创建输出的脚本:
Here is the script I am using to create the output:
-- CREATE EXTENSION tablefunc;
SELECT *
FROM CROSSTAB
(
'SELECT _tlfd.id,
_tlfd."class",
_tlfd."value"
FROM public._tlfd
WHERE _tlfd."class" = ''HBW'' or _tlfd."class" = ''HBO'' or _tlfd."class" = ''NHB''
ORDER BY 1,2'
)
AS
(
"class" int,
"HBW" text,
"HBO" text,
"NHB" text,
--"Purpose" varchar,
"value" double precision
);
运行脚本时出现此错误:
When I run the script I get this error:
ERROR: return and sql tuple descriptions are incompatible.
我不确定这意味着什么以及如何纠正错误.有人可以让我知道吗
I am not sure what this means and how to correct the error. Can someone please let me know:
- 我在脚本中做错什么了?
- 我的脚本会产生所需的输出吗?
推荐答案
这在Postgres 9.3上对我有效:
This works for me on Postgres 9.3:
SELECT *
FROM crosstab (
$$SELECT id, class, "value"
FROM _tlfd
WHERE class = ANY ('{HBW, HBO, NHB}')
ORDER BY 1,2$$
)
AS
t ( class int, -- needs a table alias!
"HBW" float8, -- resulting columns are double precision!
"HBO" float8,
"NHB" float8
-- "value" double precision -- column does not exist in result!
);
产生所需的输出.我无法提供SQLfiddle,因为无法在其中安装其他模块.
Produces the desired output. I can't provide an SQLfiddle, since one cannot install additional modules there.
- 表别名(粗体
t
) - 已删除的剩余列
"value"
- 数据列的正确数据类型(
double precision
又称float8
)
- the table alias (bold
t
) - the removed surplus column
"value"
- the correct data type for your data columns (
double precision
a.k.a.float8
)
其余的只是口味和风格的问题.我不会使用value
作为列名,因为它是
The rest is a matter of taste and style. I wouldn't use value
as column name though, since it is a reserved word in SQL.
此相关答案的详细信息:
PostgreSQL交叉表查询
Details in this related answer:
PostgreSQL Crosstab Query
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