sql - crosstab() 查询移动列

Question

我在 postgres 中使用交叉表函数。基本 SQL 是:

select distinct  
       o_location,
       co_name,
       o_date,
       o_ndate,
       o_day,
       o_hour,
       o_type
  from outputs_txt
  left join courses on o_course = co_foreign
  left join locations on o_location = l_code
 where o_date = '2011-10-10' 
 order by o_hour

我的交叉表查询是

SELECT *
  FROM crosstab(
'SELECT DISTINCT
        COALESCE(o_location, '''')
       ,o_hour AS hour
       ,c.co_name
   FROM outputs_txt AS d
   LEFT JOIN courses AS c 
     on o_course = c.co_foreign
   LEFT JOIN locations as a 
     on o_location = a.l_code
  WHERE d.o_date = ''2011-10-10'''
)
AS ct(
 o_location varchar
,hour_0  varchar
,hour_1  varchar
,hour_2  varchar
,hour_3  varchar
,hour_4  varchar
,hour_5  varchar
,hour_6  varchar
,hour_7  varchar
,hour_8  varchar
,hour_9  varchar
,hour_10 varchar
,hour_11 varchar
,hour_12 varchar
,hour_13 varchar
,hour_14 varchar
,hour_15 varchar
,hour_16 varchar
,hour_17 varchar)

问题是结果都左移了。
例如，如果一个位置的类(class)应该在 hour_8 显示，它会在 hour_0 显示。
这适用于所有地点的所有类(class)。它们都是左对齐的。

我哪里出错了？

Answer 1

由于没有样本数据，我只能猜测。以下是让我印象深刻的内容:
您的交叉表函数中没有 ORDER BY。我加了一个:

SELECT *
  FROM crosstab(
'SELECT DISTINCT
        COALESCE(o_location, '''')
       ,o_hour AS hour
       ,c.co_name
   FROM outputs_txt AS d
   LEFT JOIN courses AS c    ON o_course = c.co_foreign
   LEFT JOIN locations as a  ON o_location = a.l_code
  WHERE d.o_date = ''2011-10-10''
  ORDER BY 1,2'
)
AS ct(
 o_location varchar
,hour_0  varchar
,hour_1  varchar
,hour_2  varchar
,hour_3  varchar
,hour_4  varchar
,hour_5  varchar
,hour_6  varchar
,hour_7  varchar
,hour_8  varchar
,hour_9  varchar
,hour_10 varchar
,hour_11 varchar
,hour_12 varchar
,hour_13 varchar
,hour_14 varchar
,hour_15 varchar
,hour_16 varchar
,hour_17 varchar)

如果您想在 hour_0 之前订购，您必须在 o_hour 之前订购。我引用 manual on crosstab functions :

In practice the SQL query should always specify ORDER BY 1,2 to ensure that the input rows are properly ordered, that is, values with the same row_name are brought together and correctly ordered within the row.