If you ever want to conditionally count the number of times a particular condition occurs in SQL, you can do it in Oracle using the case andcount functions. Here's a simple example which counts the number of males/females stored in PS_PERSONAL_DATA.

select count(case when SEX = 'M' then 1 end) as MALES, count(case when SEX = 'F' then 1 end) asFEMALESfrom PS_PERSONAL_DATA

All that is happening is that the case statement returns a 1 for every instance where the gender is M or F and the count, counts each returned value of 1 giving a summary like this:

MALES FEMALES
10004 20421

The conditions in the case statement can be a lot more complex and can include sub-queries.

Conditional Counting In SQL的更多相关文章

  1. pl/sql tutorial

    http://plsql-tutorial.com/plsql-procedures.htm What is PL/SQL? PL/SQL stands for Procedural Language ...

  2. Portswigger web security academy：SQL injection

    Portswigger web security academy:SQL injection 目录 Portswigger web security academy:SQL injection SQL ...

  3. (转载)SQL Reporting Services (Expression Examples)

    https://msdn.microsoft.com/en-us/library/ms157328(v=SQL.100).aspx Expressions are used frequently in ...

  4. 如何知道SQL Server机器上有多少个NUMA节点

    如何知道SQL Server机器上有多少个NUMA节点 文章出处: How can you tell how many NUMA nodes your SQL Server has? http://i ...

  5. EntityFramework 如何查看执行的 SQL 代码？

    在 VS 调试的时候,如果我们项目中使用的是 EntityFramework,查看 SQL 执行代码就不像 ADO.NET 那样直观了,我们需要设置下,可以参考下: How can I log the ...

  6. SQL for SQLite

    语法 verb + subject + predicate commannds(命令) SQL由命令组成,以分号为结束.命令有token组成,token由white space分隔,包括空格.tab. ...

  7. SQLite Learning、SQL Query Optimization In Multiple Rule

    catalog . SQLite简介 . Sqlite安装 . SQLite Programing . SQLite statements 1. SQLite简介 SQLite是一款轻型的数据库,是遵 ...

  8. ＭＯＮＧＯＤＢ　与sql聚合操作对应图

    MongoDB 高级查询条件操作符 2012-04-25 15:35:19|  分类: MongoDB |  标签:mongodb使用  mongodb查询  |举报|字号 订阅 http://blo ...

  9. P6 Professional Installation and Configuration Guide (Microsoft SQL Server Database) 16 R1

    P6 Professional Installation and Configuration Guide (Microsoft SQL Server Database) 16 R1       May ...

随机推荐

  1. [Java] 匿名内部类

    package test.file; import java.io.File; import java.io.FilenameFilter; /** * 匿名的内部类 * @author Frost. ...

  2. 为什么wait()，notify()和notifyAll()必须在同步块或同步方法中调

    我们常用wait(),notify()和notifyAll()方法来进行线程间通信.线程检查一个条件后就行进入等待状态,例如,在"生产者-消费者"模型中,生产者线程发现缓冲区满了就 ...

  3. eclipse快捷键使用

    Eclipse的编辑功能非常强大,掌握了Eclipse快捷键功能,能够大大提高开发效率.Eclipse中有如下一些和编辑相关的快捷键.1. [ALT+/]此快捷键为用户编辑的好帮手,能为用户提供内容的 ...

  4. 批量修改java文件的包名

    需求:我复制进批量的java文件,但是包名需要用现在创建的包名 导入进来时,由于包名不一致会报错 解决办法,点击包名鼠标右键>Refactor>Rename 结果如下ok:

  5. Java中Map的用法

    Map的一般用法 1.声明一个Map : Map map = new HashMap(); 2 .向map中放值 ,注意: map是key-value的形式存放的,如: map.put("s ...

  6. esriSRGeoCSType Constants

    ArcGIS Developer Help  (Geometry)     esriSRGeoCSType Constants See Also esriSRGeoCS2Type Constants ...

  7. 零成本实现接口自动化测试 – Java+TestNG 测试Restful service

    接口自动化测试 – Java+TestNG 测试 Restful Web Service 关键词:基于Rest的Web服务,接口自动化测试,数据驱动测试,测试Restful Web Service, ...

  8. Django网站直接使用supervisor部署

    python manage.py createsuperuser python manage.py migrate 生成网站的supervisor配置文件: echo_supervisord_conf ...

  9. 共享池之六:shared pool latch/ library cache latch /lock pin 简介

    latch:library cache --desc v$librarycache; latch:library cache用于保护hash bucket.library cache lock保护HA ...

  10. java解析xml的4种经典方法

    ========================================== xml文件 <?xml version="1.0" encoding="GB2 ...