我是甲骨文新手。是否有内置关键字适用于SQL Server的相同工作?
发布于 2009-09-25 09:28:40
我认为Oracle中APPLY子句的等价物称为横向联接。Oracle中的横向联接是指将表A与输出行的函数F联接,该函数将A列作为参数。
让我们用下面的设置构建一个小示例:
SQL> CREATE OR REPLACE TYPE emp_row AS OBJECT (
2 empno NUMBER(4),
3 ename VARCHAR(10),
4 job VARCHAR(9),
5 deptno NUMBER(2)
6 );
7 /
Type created
SQL> CREATE OR REPLACE TYPE emp_tab AS TABLE OF emp_row;
2 /
Type created
SQL> CREATE OR REPLACE FUNCTION get_emp_dept(p_deptno NUMBER) RETURN emp_tab IS
2 l_result emp_tab;
3 BEGIN
4 SELECT emp_row(empno, ename, job, deptno)
5 BULK COLLECT INTO l_result
6 FROM emp
7 WHERE deptno = p_deptno;
8 RETURN l_result;
9 END get_emp_dept;
10 /
Function created
横向联接在Oracle中是自动的,没有特殊的关键字:
SQL> SELECT dept.dname, emp.empno, emp.ename, emp.job
2 FROM dept
3 CROSS JOIN TABLE(get_emp_dept(dept.deptno)) emp;
DNAME EMPNO ENAME JOB
-------------- ----- ---------- ---------
ACCOUNTING 7782 CLARK MANAGER
ACCOUNTING 7839 KING PRESIDENT
ACCOUNTING 7934 MILLER CLERK
RESEARCH 7369 SMITH CLERK
RESEARCH 7566 JONES MANAGER
RESEARCH 7788 SCOTT ANALYST
RESEARCH 7876 ADAMS CLERK
RESEARCH 7902 FORD ANALYST
SALES 7499 ALLEN SALESMAN
SALES 7521 WARD SALESMAN
SALES 7654 MARTIN SALESMAN
SALES 7698 BLAKE MANAGER
SALES 7844 TURNER SALESMAN
SALES 7900 JAMES CLERK
14 rows selected
发布于 2009-09-25 09:07:36
在Oracle中,我们可以通过使用TABLE()
函数在FROM
子句中使用管道函数。
SQL> select * from table( get_dept_emps (10) )
2 /
ENAME SAL MGR
------------------------------ ---------- ---------------------
BOEHMER 2450 SCHNEIDER
SCHNEIDER 5000
KISHORE 1300 BOEHMER
SQL>
可以像对待任何其他表一样处理它,例如,通过连接到它:
SQL> select t.*
2 , e.empno
3 from
4 table( get_dept_emps (10) ) t
5 join emp e
6 on e.ename = t.ename
7 /
ENAME SAL MGR EMPNO
---------- ---------- ---------- ----------
BOEHMER 2450 SCHNEIDER 7782
SCHNEIDER 5000 7839
KISHORE 1300 BOEHMER 7934
SQL>
发布于 2016-03-10 22:11:23
从12c开始,Oracle本机支持APPLY
和LATERAL
:https://docs.oracle.com/database/121/NEWFT/chapter12101.htm#FEATURENO10330
https://stackoverflow.com/questions/1476191
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