SQL是按另一列的值拆分一列的最有效方法

有没有更好的方法写这个？我想为每个end\u use\u data\u类型创建一个单独的值列。我还有一大堆“结束\使用\数据\类型\ id”

谢谢

select coolingvalue, heatingvalue, ventvalue, miscvalue

from analysis a

join (SELECT aeup.value coolingvalue, analysis_id FROM annual_end_use_psft aeup 
WHERE aeup.end_use_data_type_id=1) cooling ON cooling.analysis_id=a.analysis_id

join (SELECT aeup.value heatingvalue, analysis_id FROM annual_end_use_psft aeup 
WHERE aeup.end_use_data_type_id=2) heating ON heating.analysis_id=a.analysis_id

join (SELECT aeup.value ventvalue, analysis_id FROM annual_end_use_psft aeup 
WHERE aeup.end_use_data_type_id=3) ventilation ON ventilation.analysis_id=a.analysis_id

join (SELECT aeup.value miscvalue, analysis_id FROM annual_end_use_psft aeup 
WHERE aeup.end_use_data_type_id=4) misc ON misc.analysis_id=a.analysis_id

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尝试使用

联接

和条件聚合：

select a.analysis_id,
       max(case when aeup.end_use_data_type_id = 1 then aeup.value end) as coolingvalue,
       max(case when aeup.end_use_data_type_id = 2 then aeup.value end) as heatingvalue, 
       max(case when aeup.end_use_data_type_id = 3 then aeup.value end) as ventvalue,
       max(case when aeup.end_use_data_type_id = 4 then aeup.value end) as miscvalue
from analysis a join
     annual_end_use_psft aeup
     on cooling.analysis_id = a.analysis_id and
        aeup.end_use_data_type_id in (1, 2, 3, 4)
group by a.analysis_id;

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一种方法是使用pivot：对不起，我应该澄清一下——我想在select语句中再包含10列（包括analysis_id等）。不确定pivot是否仍然有效您使用的是哪种DBMS？博士后？甲骨文？谢谢戈登！我是新来的，所以这很有效（并且澄清了事情）。