如何基于日期在MYSQL数据库中SUM,GROUP和SPLIT数据

Question

表:会计

date_due        date_paid         amount_due     amount_paid    category_type
2012-08-12      2012-08-12        500            450            Income
2012-08-13      2012-08-17        200            300            Expense
2012-09-15      2012-09-13        300            300            Income
2012-09-17      2012-09-16        100            100            Income

如何生成表格如下:

date_paid       IncomeAmountPaid               ExpenseAmountPaid
2012-08         TOTAL INCOME IN AUGUST         TOTAL EXPENSE IN AUGUST
2012-09         TOTAL INCOME IN SEPT.          TOTAL EXPENSE IN SEPTEMBER

Answer 1

您可以使用以下实现CASE语句和GROUP BY:

select date_format(date_paid, '%Y-%m') date_paid,
  sum(case when category_type = 'Income' then amount_paid end) IncomePaid,
  sum(case when category_type = 'Expense' then amount_paid end) ExpensePaid
from accounting 
group by date_format(date_paid, '%Y-%m')

请参阅SQL Fiddle with Demo