两个表中的行数差异 [英] Difference in number of rows in two tables

问题描述

如何区分两个不同表中的行数?

How can I take a difference in the counts of the number of rows in two different tables?

SQL> select count(*) from dual44;

  COUNT(*)
----------
         3

SQL> select count(*) from dual;

  COUNT(*)
----------
         1

SQL> (select count(*) from dual44)
  2  minus
  3  (select count(*) from dual)
  4  ;

  COUNT(*)
----------
         3

SQL> 

我需要 2 作为结果.这两个表不一定具有相同的架构.

I need 2 as the result. The two tables might not necessarily have the same scehma.

推荐答案

减号运算符用于删除第一个结果集的所有记录，这些记录也包含在第二个结果集中.在此处使用 -(破折号)运算符.

minus operator is used to removed all records of first result set that are also contained in second. Use - (dash) operator here.

select ((select count(*) from dual44) - (select count(*) from dual)) from dual

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