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文件名称:用“选择”限定行-SQL语言基础
文件大小:5.26MB
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更新时间:2021-04-25 19:38:09
SQL 基础
用“选择”限定行
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“…查询出department为10的所有员工"
EMP
EMPNO ENAME JOB ... DEPTNO
7839 KING PRESIDENT 10
7698 BLAKE MANAGER 30
7782 CLARK MANAGER 10
7566 JONES MANAGER 20
...
EMP
EMPNO ENAME JOB ... DEPTNO
7839 KING PRESIDENT 10
7782 CLARK MANAGER 10
7934 MILLER CLERK 10
*
Limiting Rows Using a Selection
In the example on the slide, assume that you want to display all the employees in department 10. The highlighted set of rows with a value of 10 in DEPTNO column are the only ones returned. This method of restriction is the basis of the WHERE clause in SQL.