SQL Server：转置多列

Question

从这个输入到输出的最佳方式是什么？

输入：

date        id      name    info    price   qty
-----------------------------------------------
20140523    10036   ABC     B       12      100
20140523    10036   ABC     S       13      75
20140523    10034   XYZ     B       22      56
20140523    10034   XYZ     S       24      41
20151023    10037   PQR     B       30      45
20151023    10037   PQR     S       5       20

输出：

date        id      name    b_price b_qty   s_price s_qty
---------------------------------------------------------
20140523    10036   ABC     12      100     13      75
20140523    10034   XYZ     22      56      24      41
20140523    10037   PQR     30      45      5       20

Answer 1

使用条件聚合：

select date, 
       id, 
       name,
       sum(case info = 'b' then price end) as bprice,
       sum(case info = 'b' then qty end) as bqty,
       sum(case info = 's' then price end) as sprice,
       sum(case info = 's' then qty end) as sqty
from tablename
group by date, id, name