rel-ops.txt

来自「ssd7数据库系统练习一」· 文本 代码 · 共 1 行

I use select and project and join operations in my query. I use select operation to retrieve the rows which I want and the conditions are expressed in where clause. I use projection to limit the columns to be displayed. I use join operation to jion two ralative tables on condition so the information in the two tables can be retrieved.