仅在一行中求和一列？

Question

我想对一列求和，但基于不同的交易类型，并且这些总和只显示在一行中。

My SQL (SQL Server 2000) 看起来像这样：

SELECT c.customername,
       CASE WHEN t.transactiontypekey IN (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19) THEN SUM(t.tranamount) ELSE 0 END as 'Tot-Exp',
       CASE WHEN t.transactiontypekey IN (20,21,22,23,30,32,34,36) THEN SUM(t.tranamount) ELSE 0 END as 'Tot-Rev',
       CASE WHEN t.transactiontypekey IN (31,33,35,37) THEN SUM(t.tranamount) ELSE 0 END as 'Tot-Fee'
FROM customers c, transactions t
WHERE c.customerkey = t.customerkey
GROUP BY c.customername, t.transactiontypekey
ORDER BY c.customername

在上面的 SQL 中，交易类型分为费用、收入和费用，上面的输出显示为：

customernameTot-Exp  Tot-Rev    Tot-Fee
CUSTOMER1   13.3900    .0000      .0000
CUSTOMER1     .0000 549.0000      .0000
CUSTOMER1     .0000    .0000    60.0000
CUSTOMER1     .0000    .0000      .0000

我怎样才能让我的输出看起来像：

customername     Tot-Exp   Tot-Rev  Tot-Fee
CUSTOMER1         13.390    549.00   60.000

每个客户一行，仅在这一行中包含“t.tranamount”列的所有总数？

Answer 1

对CASE 表达式本身求和；

SUM(CASE WHEN t.transactiontypekey IN (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19) THEN t.tranamount ELSE 0 END) as 'Tot-Exp',

并从GROUP BY 中删除t.transactiontypekey。