sql查询将列数据放在一行中

Question

我在名为data_tab

的表格中有以下数据

sn  code
2   101
2    
2   202
5   103
5   
5

如何查询在一行中查看结果，例如

sn  code1  code2   code3
2   101            202
5   103  

Answer 1

嗨这给出了预期的输出......看看here

select sn,
        max(decode(rn,1,code)) as CODE_1
       ,max(decode(rn,2,code)) as CODE_2
       ,max(decode(rn,3,code)) as CODE_3

from
(
select sn,
      code,
      row_number() over (partition by sn order by null ) rn
from test
  )

group by sn