Question

Oracle数据库中存在一种情况，我想从两个具有相同列的表创建报告表格A包含id, code, name，表格B也包含id, code, name 现在我想创建一个报告，对两个表中的数据进行计数和分组，并给出如下结果：

Id1, code1, name1, count (the occurrence of this combination in both tables)

Id2, code2, name2, count (the occurrence of this combination in both tables)

如何使用查询实现上述结果？重要的事实是，有时某个特定项目可能在一个表中找不到，因此总计数将是在另一个表中找到的计数。可能的结果是

idn, coden, namen, count of occurrence which found in one of the tables

Answer 1

写下这个：

SELECT id, code, name, count(*)
FROM (
  SELECT id, code, name FROM table1
  UNION ALL
  SELECT id, code, name FROM table2
) t
GROUP BY id, code, name

如果您想保留每个(id, code, name)组合出现在每个表中的次数，您可以使用辅助列：

SELECT 
  id, 
  code, 
  name, 
  count(*) AS "Occurrence in both tables",
  count(CASE WHEN t = 'table1' THEN 1 END) AS "Occurrence in table1",
  count(CASE WHEN t = 'table2' THEN 1 END) AS "Occurrence in table2"
FROM (
  SELECT id, code, name, 'table1' AS t FROM table1
  UNION ALL
  SELECT id, code, name, 'table2' AS t FROM table2
) t
GROUP BY id, code, name

Answer 2

$credential = Get-Credential

如果你想计算结果那么

select id,name,count from
(
select id as id , name as name, count as count from table1
union
select id as id , name as name, count as count from table2
)

从两个表中聚合相同的记录

2 个答案: