Question

我在数据库中有一个表格，显示组织的支出

Office   Year  Quarter  Computer  Keyboard  Monitor  Total
Office1  2014  Q1       1000      300       400      1700
Office1  2014  Q2        400      100         0       500
Office1  2014  Q3        500        0       300       800
Office2  2014  Q1       1500      250       250      2000
Office2  2014  Q2        400      250       250       900
Office2  2014  Q3       1000      100       100      1200

我希望表格像

office   Year  Usage     Q1    Q2   Q3
Office1  2014  Computer  1000  400   500
Office1  2014  Keyboard   300  100     0
Office1  2014  Monitor    400    0   300
Office1  2014  Total     1700  500   800
Office2  2014  Computer  1500  400  1000
Office2  2014  Keyboard   250  250   100
Office2  2014  Monitor    250  250   100
Office2  2014  Total     2000  900  1200

我尝试过以下代码但仅显示office 1的用法

SELECT usage,
       MAX(CASE WHEN quarter = 'q1' THEN value END) Q1,
       MAX(CASE WHEN quarter = 'q2' THEN value END) Q2,
       MAX(CASE WHEN quarter = 'q3' THEN value END) Q3
  FROM
(
  SELECT quarter, usage,
         CASE usage 
            WHEN 'computer' THEN COMPUTER
            WHEN 'keyboard' THEN KEYBOARD
            WHEN 'monitor' THEN MONITOR
            WHEN 'total' THEN TOTAL

         END value
    FROM OfficeUsageTable t CROSS JOIN
  (
    SELECT 'Computer' usage UNION ALL
    SELECT 'Keyboard' UNION ALL
    SELECT 'Monitor' UNION ALL
    SELECT 'Total'
  ) c
) q
 GROUP BY usage;

显示的表格仅适用于office1 ie

office   Year  Usage     Q1    Q2   Q3
Office1  2014  Computer  1000  400  500
Office1  2014  Keyboard   300  100    0
Office1  2014  Monitor    400    0  300
Office1  2014  Total     1700  500  800

我希望显示两个办公室的所有数据。请协助。

Answer 1

USAGE是MySQL reserved word。因此，建议不要在（子）查询中使用列/别名。相反，在这个答案中，子查询中使用了'usg'。

您的查询中需要进行少量更改，如下所示：

更改1 ：您需要在主要表office中加入year和OfficeUsageTable。

更改2 ：您需要按office和usg字段进行分组。

尝试以下方法：

SELECT office as 'Office', year as 'Year', usg as 'Usage',
  MAX(CASE WHEN quarter = 'q1' THEN value END) Q1,
  MAX(CASE WHEN quarter = 'q2' THEN value END) Q2,
  MAX(CASE WHEN quarter = 'q3' THEN value END) Q3
FROM
(
  SELECT office, year, quarter, usg,
    CASE usg 
      WHEN 'computer' THEN COMPUTER
      WHEN 'keyboard' THEN KEYBOARD
      WHEN 'monitor' THEN MONITOR
      WHEN 'total' THEN TOTAL
    END value
  FROM OfficeUsageTable t CROSS JOIN
  (
    SELECT 'Computer' as usg UNION ALL
    SELECT 'Keyboard' UNION ALL
    SELECT 'Monitor' UNION ALL
    SELECT 'Total'
  ) c
) q
GROUP BY office, usg

我想将行更改为列，但仅显示office1，我想要两个办公室

1 个答案: