Question

我有一个包含6列的预订表，名为booked_start，booked_stop，used_start，used_stop，invoice_start，invoice_stop。值是浮点数。我想得到一个值大于0的行的总和，但我也希望它计算说used_stop - used_start。

目前正在与此合作：

SELECT
    room,
    IF( booked_stop_time > 0, sum(booked_stop_time - booked_start_time), 0 ) as booked,
    IF( used_stop_time > 0, sum(used_stop_time - used_start_time), 0 ) as used,
    IF( invoice_stop_time > 0, sum(invoice_stop_time - invoice_start_time), 0 ) as invoice
FROM bookings

问题是如果expr1返回false，它将重置总和。我只想将行值添加到总和中，如果它高于0。

我也试过使用一个案例，但这并没有真正起作用。也许我应该在PHP中进行计算呢？

Answer 1

这应该有效：

SELECT
  room,
  SUM(
    CASE WHEN booked_stop_time - booked_start_time > 0
      THEN booked_stop_time - booked_start_time
      END
  ) AS booked,
  SUM(
    CASE WHEN used_stop_time - used_start_time > 0
      THEN used_stop_time - used_start_time
      END
  ) AS used,
  SUM(
    CASE WHEN invoice_stop_time - invoice_start_time > 0
      THEN invoice_stop_time - invoice_start_time
      END
  ) AS invoice
FROM bookings

关注booked值：

如果booked_stop_time - booked_start_time大于零，则CASE会返回booked_stop_time - booked_start_time，因此它会包含在总和中。
CASE没有任何其他条件，因此如果booked_stop_time - booked_start_time 不大于零，则CASE将返回NULL，这意味着该行不包括在总和中。

Answer 2

你可以这样做：

SELECT
    room,
    SUM(IF( booked_stop_time > 0, booked_stop_time - booked_start_time, 0 )) as booked,
    SUM(IF( used_stop_time > 0, used_stop_time - used_start_time, 0 )) as used,
    SUM(IF( invoice_stop_time > 0, invoice_stop_time - invoice_start_time, 0 )) as invoice
FROM bookings

它返回0，因为当您的IF条件不满足时，它会将0设置为最终值，因此只需使用IF包裹SUM。

Answer 3

你可以试试这个

SELECT
    room,

    SUM( 
          IF( booked_stop_time > 0 and booked_start_time IS NOT NULL, 
                       (booked_stop_time - booked_start_time), 0 ) 
      ) AS booked,

   SUM( 
       IF(used_stop_time > 0 AND used_start_time IS NOT NULL,
                            (used_stop_time - used_start_time) , 0 ) 
      ) AS used,

   SUM(
        IF(invoice_stop_time > 0 AND invoice_start_time IS NOT NULL, 
                            (invoice_stop_time - invoice_start_time) , 0)   
       ) AS invoice

WHERE booked_stop_time > 0 
OR  used_stop_time > 0 
OR invoice_stop_time > 0

使用带有if表达式的sql计算多个值

3 个答案: