我需要横向子查询的帮助：
是否可以使用动态生成的列名执行它？
我尝试过，但我做错了：
-- table containing column names as values
nov=# select rsi.display_field from corp_resumesectionitem rsi limit 15;
display_field
-----------------------------
resume_attribute_00064_13
resume_attribute_00065_13
resume_attribute_00066_13
resume_attribute_00067_18_1
resume_attribute_00067_18_2
resume_attribute_00068_1
resume_attribute_00069_1
resume_attribute_00070_13
resume_attribute_00071_13
resume_attribute_00072_13
resume_attribute_00082_1
resume_attribute_00083_1
resume_attribute_00084_6
resume_attribute_00085_13
resume_attribute_00086_3
(15 rows)
-- import.vw_rpt_resume table contains several colum with names corresponding to the display_field values, such as 'resume_attribute_00064_13', 'resume_attribute_00065_13':
nov=# select column_name from information_schema.columns where table_name='vw_rpt_resume'; column_name
------------------------------------
user_id
warehouse_resume_attribute_user_id
resume_attribute_000m1_2
resume_attribute_00032_13
resume_attribute_00052_13
resume_attribute_00053_13
resume_attribute_00057_4
resume_attribute_00058_7
resume_attribute_00059_6
resume_attribute_00061_3
...
...
resume_attribute_00094_18_1
resume_attribute_00094_18_2
resume_attribute_00095_1
resume_attribute_00096_13
resume_attribute_00097_13
resume_attribute_00098_7
resume_attribute_00099_2
resume_attribute_00100_13
resume_attribute_00101_13
resume_attribute_00102_13
(55 rows)
我需要在LATERAL子查询中使用动态列名执行查询，不要搞砸了......
之类的东西（这更像是伪代码，但它仅仅是为了提出一个想法）：
select * from (
select
rsi.display_field as df,
subq.*
from corp_resumesectionitem rsi, lateral (
execute 'select user_id, unnest(string_to_array(' || rsi.display_field '' ', ',')) as val, ' || rsi.display_field || ' as col_name from import.vw_rpt_resume subq'
)
-- but this is not working...
每个横向查询都应该是这样的：
select * from (
select distinct r.user_id, r.val, m.name_display, l.rsal_value_id, l.rsal_title, m.display_field, l.culture_id
from (
select user_id,
unnest(string_to_array(resume_attribute_00032_13, ',')) as val,
'resume_attribute_00032_13' as col_name from import.vw_rpt_resume
) as r
inner join import.custom_fields_mapping m
on r.col_name::text = m.display_field
inner join import.vw_rpt_resume_section_attribute_value_local as l
on r.val = l.rsal_value_id) as dd;
结果像这样的结果：
user_id | val | name_display | rsal_value_id | rsal_title | display_field | culture_id
---------+-----+-----------------------------------------+---------------+-----------------+---------------------------+------------
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 1
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 10
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 11
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 12
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 13
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 14
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 15
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 16
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 17
56 | 226 | Skills & Knowledge - Skills & Knowledge | 226 | Being resilient | resume_attribute_00032_13 | 18
但我得到了这个：
df | user_id | val | col_name
---------------------------+---------+---------------------------+---------------------------
resume_attribute_00064_13 | 525 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 0 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 542 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 326 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 564 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 86 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 162 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 603 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 803 | resume_attribute_00064_13 | resume_attribute_00064_13
resume_attribute_00064_13 | 246 | resume_attribute_00064_13 | resume_attribute_00064_13
对此有何帮助？
错误/查询样本无效：
select * from (
select
display_field as df,
subq.*
from company_resumesectionitem rsi, lateral (
select
user_id,
unnest(string_to_array(format(rsi.display_field), ',')) as val,
format(rsi.display_field::text) as col_name
from import.vw_rpt_resume) subq
) as sel;