LibreOffice Base - SQL 查询困难

Question

我有一个包含 3 列的 table，例如 Food、Type 和 Taste。

列 Food 可以有任何内容
列 Type 可能有 'Fruit' 或 'Vegetable' 作为可能的值
列 Taste 可能有 'Bad'、'Good' 或 'Delicious' 作为可能的值

我试图得到（到目前为止运气不好）一个 SQL 语句，它会产生一个 table 像：

            Bad       Good    Delicious   Total
Fruit        05         09           16      20
Vegetables   12         20           03      35
Total        17         29           19      55

如果输出 table 上的数字是每个 Type / Taste 组合的 table 中有多少 Food 的计数。

如何实现？

Answer 1

前两行可以在一个带有子查询子句的查询中完成：

SELECT X."Type", 
       SUM(X."Bad") AS "Bad",
       SUM(X."Good") AS "Good",
       SUM(X."Delicious") AS "Delicious",
       SUM(X."Total") AS "Total" 
FROM (SELECT "Type",
          CASEWHEN("Taste" = 'Bad',1,0) AS "Bad",
          CASEWHEN("Taste" = 'Good',1,0) AS "Good",
          CASEWHEN("Taste" = 'Delicious',1,0) AS "Delicious",
          1 AS "Total" FROM "YourTableName") X 
GROUP BY "Type"

子查询创建列 "Bad"、"Good" 和 "Delicious"，每列中有 1 或 0，然后查询的外部将所有值相加。

要获得底部的总计行，您必须使用 UNION ALL，这是基本解析器不支持的。要使此查询正常工作，您需要打开 Edit→Run SQL Directly 选项。（这将禁用某些需要解析器的表单和报告功能 - 这可能对您的使用无关紧要，但仅供参考，如果您稍后在表单或报告中使用此查询。）

您将 UNION ALL 使用的查询基本上是相同的查询，只是不按类型分组。所以总计：

SELECT X."Type", 
       SUM(X."Bad") AS "Bad",
       SUM(X."Good") AS "Good",
       SUM(X."Delicious") AS "Delicious",
       SUM(X."Total") AS "Total" 
FROM (SELECT "Type",
          CASEWHEN("Taste" = 'Bad',1,0) AS "Bad",
          CASEWHEN("Taste" = 'Good',1,0) AS "Good",
          CASEWHEN("Taste" = 'Delicious',1,0) AS "Delicious",
          1 AS "Total" FROM "YourTableName") X 
GROUP BY "Type"

UNION ALL

SELECT 'Total' AS "BottomTotal",
       SUM(Y."Bad"),
       SUM(Y."Good"),
       SUM(Y."Delicious"),
       SUM(Y."Total") 
FROM (SELECT CASEWHEN("Taste" = 'Bad',1,0) AS "Bad",
          CASEWHEN("Taste" = 'Good',1,0) AS "Good",
          CASEWHEN("Taste" = 'Delicious',1,0) AS "Delicious",
          1 AS "Total" FROM "YourTableName") Y 
GROUP BY "BottomTotal"

确保始终将 "YourTableName" 替换为您的实际 table 姓名。

LibreOffice Base - SQL 查询困难

LibreOffice Base - Difficulties with SQL query

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