SQL 查询 - 按到期月透视贷款摘要

Question

这看起来很简单，但我正在努力解决这个问题。

我有一个贷款数据表，我想对每个月的到期付款进行透视和汇总。这类似于“静态池分析”，将每个贷款池作为行，将月份作为列。您可以使用此SQL Fiddle 查看示例数据。

我创建了一个90 second screencast 来更好地解释我需要的数据透视和汇总结果，如果有帮助的话。感谢您的帮助！

Answer 1

如果它不需要是动态的，在 SUM 中使用 CASE WHEN 或 IF 语句应该在 MySQL 中充当 PIVOT：

SELECT 
  PoolMonth, 
  SUM(OriginationAmt) AS Origination,
  SUM(IF(PmtDue = 201512, AmtPaid, 0)) AS `201512`,
  SUM(IF(PmtDue BETWEEN 201512 AND 201601, AmtPaid, 0)) AS `201601`,
  SUM(IF(PmtDue BETWEEN 201512 AND 201602, AmtPaid, 0)) AS `201602`
FROM
  Loans
GROUP BY
  PoolMonth;

http://sqlfiddle.com/#!9/47701/16

获取 OriginationAmt 的总数有点冗长，PoolMonth/PmtDue 的运行总数，并且只输出最新的运行总数，没有硬编码任何东西，但是我们开始 :-)

SELECT
  t.PoolMonth,
  t.TtlOriginationAmt,
  t.PmtDue,
  t.RtAmtPaid
FROM
  (
    SELECT 
      l.PoolMonth,
      l.OriginationAmt,
      orig.TtlOriginationAmt,
      l.PmtDue,
      /* Row_Number() equivalent for MySQL http://blog.sqlauthority.com/2014/03/09/mysql-reset-row-number-for-each-group-partition-by-row-number/ */
      /* Assign a Row Number for each Payment Due month for the individual Pool month in ascending order (ORDER BY clause important in this subquery) */
      @RowNumber := CASE WHEN @PoolMonth = l.PoolMonth AND @PmtDue = l.PmtDue THEN @RowNumber + 1 ELSE 1 END AS PoolPmtRowNumber,
      /* Use the total count of PmtDue month rows for each PoolMonth so we can limit our results to the final row */
      lr.PoolPmtLastRow,
      l.AmtPaid,
      /* Running total of Amount Paid for the individual Pool month in order of Payment Due month (ORDER BY clause important in this subquery) */
      @RtAmtPaid := CASE WHEN @PoolMonth = l.PoolMonth THEN @RtAmtPaid + l.AmtPaid ELSE l.AmtPaid END AS RtAmtPaid,
      /* Keep track of the Pool month we're totalling */
      @PoolMonth := l.PoolMonth,
      /* Keep track of the Payment Due month we're ordering */
      @PmtDue := l.PmtDue
    FROM
      Loans l
    JOIN
      /* Get the Total Origination Amount */
      (SELECT PoolMonth, SUM(OriginationAmt) AS TtlOriginationAmt FROM Loans GROUP BY PoolMonth) orig ON orig.PoolMonth = l.PoolMonth
    JOIN
      /* Get the total number of records by Pool/Payment due month so we can filter to the last row */
      (SELECT PoolMonth, PmtDue, COUNT(1) AS PoolPmtLastRow FROM Loans GROUP BY PoolMonth, PmtDue) AS lr ON lr.PoolMonth = l.PoolMonth AND lr.PmtDue = l.PmtDue
    CROSS JOIN
      /* Reset the variables we need for tracking */
      (SELECT @RtAmtPaid:=0,@PoolMonth:=0,@PmtDue:=0,@RowNumber:=0) var
    /* Order by Pool/Payment Due month */
    ORDER BY
      l.PoolMonth,
      l.PmtDue
  )t
WHERE
  /* Filter to the last row */
  t.PoolPmtRowNumber = t.PoolPmtLastRow;

http://sqlfiddle.com/#!9/47701/45

从那里开始，应该很容易在 Excel 或其他任何地方转换您的结果。