mysql select exists

Similarly, using the goods table to practice subqueries, the table structure is as follows:All data (cat_id associated with category.cat_id):Category table:Mingoods (test when connecting queries)First, sub-query 1,where sub-query: The result of the

Installation RequirementsInstallation Environment: CentOS-6.3Installation Method: source code compilation installationSoftware Name: mysql-cluster-gpl-7.2.6-linux2.6-x86_64.tar.gzDownload Address: http://mysql.mirror.kangaroot.net/Downloads/Software

MySQL常用指令，java，php程序员，数据库工程师必备。程序员小冰常用资料整理MySQL common commands (for reference)The most common display commands are:1. Display the list of databases.show databases;2. Display the data table in the library:Use MySQL;Show tables;3, display the

How to configure MySQL database server on CentOS BitsCN.com accidentally found CentOS Professional Forum, remember: http://www.centospub.com As a result, the initial learning configuration This environment: CentOS system, Mysql-server (version

I met a strange question about exists today. The first statement is as follows: Select count (1) from the APPLY t WHERE EXISTS ( select r.apply_id from record R WHERE t.apply_id = r.apply_id ); The resulting results are: 89584 The

One query is as follows: 1 SELECTc.CustomerId, c.CompanyName   2 FROMCustomers c   3 WHEREEXISTS(   4

A MySQL bug about exists, MySQLexistsbug Today, I encountered a strange question about exists. The first statement is as follows: SELECTcount(1)FROMAPPLY tWHEREEXISTS (SELECTr.APPLY_IDFROMRECORD rWHEREt.APPLY_ID = r.APPLY_ID); Result: 89584 The

SQL query in the in, exists, not in, not exists usage and difference, sqlexists 1. in and exists In connects the External table to the internal table as a hash (Dictionary set), while exists loops the External table and queries the internal table

Usage and difference of in, exists, not in, and not exists in SQL queries 1. in and exists In connects the External table to the internal table as a hash (Dictionary set), while exists loops the External table and queries the internal table after

How to configure MySQL database server on CentOS This environment: CentOS system, Mysql-server (version forgot, because it was installed using yum) The process is as follows (reprinted, according to detailed installation requirements, slightly add