对不同的列使用排名

Question

我的 table 看起来像这样：

CITY     TOPIC      RANK
NY       FOOTBALL   1
NY       BASKETBALL 2
....
NY       BASEBALL   10
WS       FOOTBALL   1
....

我要的是这个：

CITY     TOP 1      TOP 2      ...      TOP 10
NY       FOOTBALL   BASKETBALL ...      BASEBALL
WS       FOOTBALL   ............................

我该怎么做？非常感谢！

Answer 1

MySQL 中没有直接上调。您需要在 Query 中手动创建列。例如

select City, max(case when Rank=1 then TopiC end) as Top1, max(case when Rank=2 then Topic end) as Top2, . . . max(case when Rank=10 then Topic end) as Top10 from Table group by City

Answer 2

你可以试试

SELECT * FROM
(
SELECT City,Topic, 
 'Top '+ cast(Rank as varchar(10)) AS TopRank
 FROM TableName
 ) T
PIVOT 
(
max(topic) 
FOR TopRank IN ([Top 1], [Top 2],[Top 10])
) as pvt

Answer 3

我会简单地使用条件聚合：

select city,
       max(case when rank = 1 then topic end) as top_1,
       max(case when rank = 2 then topic end) as top_2,
       . . . 
       max(case when rank = 10 then topic end) as top_10
from t
group by city;

这假设 rank 没有关系。如果你有领带，你可能更喜欢 listagg() 而不是 max().

对不同的列使用排名

Use rank for different columns

sql

oracle

rank