Question

我希望使用嵌套的SELECT将code_2的结果看作code_1的结果。你能帮帮我吗？我使用数据库 - Oracle PL / SQL Developer 非常感谢提前

code_1：

SELECT DISTINCT eventattribute1
FROM   table1 partition(m201302) 
WHERE  eventattribute22 = 'EURO' 
       AND eventattribute13 = 'MC_PO_ROAM' 
       AND eventattribute14 != 'T' 
       AND event_cost != '0' 
GROUP  BY eventattribute1

CODE_2：

SELECT Numtodsinterval(Sum(To_char(To_date(duration, 'HH24:MI:SS'), 
                           'HH24') * 
                                  3600 + 
                                                      To_char( 
                                  To_date(duration, 'HH24:MI:SS'), 
                                                      'MI') 
                                                      * 60 + 
                                  To_char(To_date(duration, 
                                          'HH24:MI:SS'), 'SS')), 'second') AS 
       SUMTOTAL 
FROM   table1 partition(m201302)

Answer 1

要将此作为嵌套选择，您只需将第二个查询添加到第一个查询的选择行。它返回一个值和一行，所以没关系。从概念上讲，这是：

SELECT eventattribute1,
       <code2>
FROM   table1 partition(m201302) 
WHERE  eventattribute22 = 'EURO' 
       AND eventattribute13 = 'MC_PO_ROAM' 
       AND eventattribute14 != 'T' 
       AND event_cost != '0' 
GROUP  BY eventattribute1

（distinct是不必要的。）

在实践中，这看起来有点糟糕：

SELECT eventattribute1,
       (SELECT Numtodsinterval(Sum(To_char(To_date(duration, 'HH24:MI:SS'), 
                       'HH24') * 
                              3600 + 
                                                  To_char( 
                              To_date(duration, 'HH24:MI:SS'), 
                                                  'MI') 
                                                  * 60 + 
                              To_char(To_date(duration, 
                                      'HH24:MI:SS'), 'SS')), 'second') AS SUMTOTAL 
        FROM   table1 partition(m201302)
       ) as SUMTOTAL
FROM   table1 partition(m201302) 
WHERE  eventattribute22 = 'EURO' 
       AND eventattribute13 = 'MC_PO_ROAM' 
       AND eventattribute14 != 'T' 
       AND event_cost != '0' 
GROUP  BY eventattribute1

另一种方法是使用分析函数，因为此查询不需要嵌套选择。

在回复您的评论时，一种方法是相关子查询：

SELECT eventattribute1,
       (SELECT Numtodsinterval(Sum(To_char(To_date(duration, 'HH24:MI:SS'), 
                       'HH24') * 
                              3600 + 
                                                  To_char( 
                              To_date(duration, 'HH24:MI:SS'), 
                                                  'MI') 
                                                  * 60 + 
                              To_char(To_date(duration, 
                                      'HH24:MI:SS'), 'SS')), 'second') AS SUMTOTAL 
        FROM   table1 partition(m201302) t1
        where t1.eventattribute1 = table1.eventattribute1
       ) as SUMTOTAL
FROM   table1 partition(m201302) 
WHERE  eventattribute22 = 'EURO' 
       AND eventattribute13 = 'MC_PO_ROAM' 
       AND eventattribute14 != 'T' 
       AND event_cost != '0' 
GROUP  BY eventattribute1;

更简单的方法可能是将其直接移动到聚合中。。但您可能需要使用where子句中的条件;

SELECT eventattribute1,
       Numtodsinterval(Sum(To_char(To_date(duration, 'HH24:MI:SS'), 
                       'HH24') * 
                              3600 + 
                                                  To_char( 
                              To_date(duration, 'HH24:MI:SS'), 
                                                  'MI') 
                                                  * 60 + 
                              To_char(To_date(duration, 
                                      'HH24:MI:SS'), 'SS')), 'second') AS SUMTOTAL 
FROM   table1 partition(m201302) 
WHERE  eventattribute22 = 'EURO' 
       AND eventattribute13 = 'MC_PO_ROAM' 
       AND eventattribute14 != 'T' 
       AND event_cost != '0' 
GROUP  BY eventattribute1

如何做嵌套SELECT

1 个答案: