Question

这些是我在显示数据时必须使用的表

data1

和我们用来加入表格的查询

table1
-----------------------------------------------------
col1                col2        id
1223                ram         254
1232                rajesh      345


table 2
--------------------------------------
id              col5        col6        col7     col8
254             1223-1      8789        abc      67
254             1223-2      8790        efg      87
254             1223-3      8791        bcd      67
254             1223-4      8792        abc      87
345             1232-1      7897        cdf      89
345             1232-2      7898        cdf      60

使用上述查询时的输出

select 
        t1.col1,
        listagg(t2.col5,',') within group(order by t2.col6)as col5,
        listagg(t2.col7,',') within group(order by t2.col6)as col7,
          listagg(t2.col8,',') within group(order by t2.col6)as col8
     from 
            table1 t1
            join table2 t2 on t1.id=t2.id;
        group by col1

预期结果：

 col1            col5                      col7    col8
---------------------------------------------------------------------- 
1233        1223-1,1223-2,1223-3,1223-4     abc,efg,bcd,abc     67,87,67,87
 1232       1232-1,1232-2                   cdf,cdf                89,60

我们不应该使用Wm_concat，因为它没有文档记录。 Col5，col7和Col8应仅按col6排序。

Answer 1

这是一个解决方案，当按col6排序时，它返回所请求列的第一个不同事件。它使用一个中间步骤来首先消除重复项，然后执行最终的listagg：

with t3 as (
SELECT T1.COL1
     , T2.COL6
     , case row_number() over (partition by t1.col1, t2.col5 order by t1.col1)
           when 1 then t2.col5  -- Output the first occurrance of Col5
           else null
       end COL5
     , case row_number() over (partition by t1.col1, t2.col7 order by t1.col1)
           when 1 then t2.col7  -- Output the first occurrance of Col7
           else null
       end COL7
     , case row_number() over (partition by t1.col1, t2.col8 order by t1.col1)
           when 1 then t2.col8  -- Output the first occurrance of Col8
           else null
       end COL8
  FROM TABLE1 T1
  JOIN TABLE2 T2
    ON T1.ID = T2.ID
)
 select t3.col1
      , listagg(COL5,',') WITHIN GROUP (ORDER BY T3.COL6) COL5
      , listagg(COL7,',') WITHIN GROUP (ORDER BY T3.COL6) COL7
      , listagg(COL8,',') WITHIN GROUP (ORDER BY T3.COL6) COL8
   from t3
  group by col1;

结果：

COL1    COL5                        COL7        COL8
------- --------------------------- ----------- -----
1223    1223-1,1223-2,1223-3,1223-4 ABC,EFG,BCD 67,87
1232    1232-1,1232-2               CDF         89,60

如何在oracle12c中使用listagg仅显示唯一值

1 个答案: