技巧:对于含可空字段、非空但是含有默认值的字段、自增字段,可以不用在 insert 后的字段列表里面出现,values 后面只写对应字段名称的 value,这些没写的字段可以自动设置为 NULL、默认值、自增的下一个数字,这样在某些情况下可以大大缩短 SQL 语句的复杂性。 例如,只对表中的 ename 和 sal 字段显式插入值:mysq...
This chapter demonstrates the data manipulation language (DML), showing the syntax and plenty of examples. DML commands are used in SQL to add, modify, and remove rows of data in database tables. Transaction control using ROLLBACK and COMMIT commands, among others, plus the MERGE command, ...
we will delve into SQL commands, their types, syntax, and practical examples to empower you with the knowledge to interact with databases effectively.
Nearly all these features follow standard SQL syntax and functionality, so any SQL reference can be used for more information. There are 4 basic commands for manipulating data in SQL, corresponding to the standard create, read, update and delete (CRUD) operations: IN...
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 21671 to server version: 5.1.9-beta-log Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql> use sakila Database changed ...
SQL The Structured Query Language that is standard for performing database operations. Often divided into the categoriesDDL,DML, andqueries. MySQL includes some additional statement categories such asreplication. SeeChapter 10,Language Structurefor the building blocks of SQL syntax,Chapter 12,Data Types...
// DLBLempldem,'idms.sqldemo.empldemo',1999/365,DA // EXTENT SYSnnn,nnnnnn,,,ssss,11 // ASSGN SYSnnn,DISK,VOL=nnnnnn,SHR // DLBLinfodem,'idms.sqldemo.infodemo',1999/365,DA // EXTENT SYSnnn,nnnnnn,,,ssss,6 // ASSGN SYSnnn,DISK,VOL=nnnnnn,SHR ...
Commands end with ; or \g. Your MySQL connection id is 4663988 Server version: 8.0.24-v24-txsql-22.1.4-20230224 Source distribution Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. ...
运行时动态注册切换数据源,自动生成SQL(DDL/DML/DQL),读写元数据,对比数据库结构差异。适配100+关系/非关系数据库。 常用于动态场景的底层支持,如:数据中台、可视化、低代码后台、工作流、自定义表单、异构数据库迁移同步、物联网车联网数据处理、数据清洗、运行时自定义
HiveSQLLanguage Manual:Commands,CLIs,Data Types,DDL(create/drop/alter/truncate/show/describe),Statistics(analyze),Indexes,Archiving,DML(load/insert/update/delete/merge,import/export,explain plan),Queries(select),Operators and UDFs,Locks,Authorization ...