数据库sql命令大全

数据库sql命令大全，几乎囊括了所有常用的sql命令，记住这些，差不多基础是有了

sql语言艺术-中文版

You can hardly interview a young developer today who doesn't claim a good working knowledge of SQL, the lingua franca of database access, a standard part of any basic IT course. This claim is usually reasonably true, if you define knowledge as the ability to obtain, after some effort, functionally correct results. However, enterprises all over the world are today confronted with exploding volumes of data. As a result, "functionally correct" results are no longer enough: they also have to be fast. Database performance has become a major headache in many companies. Interestingly, although everyone agrees that the source of performance issues lies in the code, it seems accepted everywhere that the first concern of developers should be to provide code that workswhich seems to be a reasonable expectation. The thought seems to be that the database access part of their code should be as simple as possible, for maintenance reasons, and that "bad SQL" should be given to senior database administrators (DBAs) to tweak and make run faster, with the help of a few magic database parameters. And if such tweaking isn't enough, then it seems that upgrading the hardware is the proper course to take.