SQL语言的介绍以及语法（关键字）

SQL语言的介绍

https://www.runoob.com/sql/sql-tutorial.html
https://www.runoob.com/sql/sql-intro.html

SQL语法（基础）

https://www.runoob.com/sql/sql-syntax.html
https://www.runoob.com/sql/sql-select.html
https://www.runoob.com/sql/sql-distinct.html
https://www.runoob.com/sql/sql-where.html
https://www.runoob.com/sql/sql-and-or.html
https://www.runoob.com/sql/sql-orderby.html
https://www.runoob.com/sql/sql-insert.html
https://www.runoob.com/sql/sql-update.html
https://www.runoob.com/sql/sql-delete.html