This is the third of a series of posts based on a presentation I did at the Barcelona Ruby Conference called “20,000 Leagues Under ActiveRecord.” (posts: one two and video). Preparing for this presentation over the Summer, I decided to read through p…
SQL Fundamentals || Oracle SQL语言 Capabilities of the SELECT Statement(SELECT语句的功能) Data retrieval from data base is done through appropriate and efficient use of SQL. Three concepts from relational theory encompass the capability of the SELECT statem…
A SELECT statement that assigns a value to a variable must ... (向变量赋值的 SELECT 语句不能与数据检索操作结合使用 ) 总结一句话,一行语句中,要么都是赋值,要么都是查询,不能既有赋值又有查询 [ 错误 ] select @classname=classname,@chargeteacher from classes where classid=@classid [ 错误 ] select @clas…
Cannot resolve collation conflict between . 解决方案: COLLATE Chinese_PRC_CI_AS 例子: SELECT A.Name FROM A WHERE A.Code COLLATE Chinese_PRC_CI_AS in (select A_Code COLLATE Chinese_PRC_CI_AS from B )…
Select specific or all columns select * from 表名 select * from Student select 列名,列名... from 表名 select name,age,email from Student Distinct rows select distinct 列名 from 表名 select distinct name from Student Filtering with where clause(子句) select * from…
https://github.com/mybatis/mybatis-dynamic-sql MyBatis Dynamic SQL What Is This? This library is a framework for generating dynamic SQL statements. Think of it as a typesafe SQL templating library, with additional support for MyBatis3 and Spring…
This is the last in a series of Postgres posts that Pat Shaughnessy wrote based on his presentation at the Barcelona Ruby Conference. You can also watch the video recording of the presentation. The series was originally published on his personal blog…
MySQL and Postgres command equivalents (mysql vs psql) 博客分类: Database From: http://blog.endpoint.com/2009/12/mysql-and-postgres-command-equivalents.html Posted by Greg Sabino Mullane |December 24, 2009 Users toggling between MySQL and Postgres are…
