过程中的光标并调用过程

Question

需要帮助了解如何在过程中使用游标变量。并使用匿名块调用过程 6 次来运行一组查询。试图弄清楚这一点让我很头疼，提前感谢您的帮助。

    CREATE OR REPLACE PROCEDURE City_Jail_SP
     (lv_query IN NUMBER,
      lv_out out VARCHAR2)
     AS
     cursor qry_lvl IS
BEGIN
   OPEN qry_lvl;
   LOOP
   FETCH INTO
    IF chioce = 1 THEN SELECT AVG(COUNT(*))
    FROM crime_officers
    GROUP BY officer_id;
    
    ELSIF chioce = 2 THEN SELECT MIN(Fine_amount)
    FROM Crime_charges;  
    
    ELSIF chioce = 3 THEN COLUMN (hearing_date-date_charged) HEADING DAYS
    SELECT crime_id, Classification, date_charged, hearing_date,
    ( hearing_date-date_charged)
    FROM crimes
    WHERE hearing_date-date_charged >14;
    
    ELSIF choice = 4 THEN select cl.criminal_id, cl.last, cl.first, cc.Crime_code, cc.Fine_amount
    FROM criminals cl
    JOIN crimes cr
    ON cr.criminal_id = cl.criminal_id
    JOIN crime_charges cc
    ON cc.crime_id = cr.crime_id;
   
    ELSIF chioce = 5 THEN SELECT LAST, FIRST
    FROM officers JOIN crime_officers USING (officer_id)
    JOIN crimes USING (crime_id)
    GROUP BY (LAST, FIRST)
    HAVING COUNT(crime_id)>(SELECT AVG(COUNT(crime_id))
    FROM crimes JOIN crime_officers using (crime_id)
    GROUP BY officer_id);
    
    ELSIF choice = 6 THEN SELECT DISTINCT FIRST, LAST
    FROM criminals JOIN crimes USING (criminal_id)
    JOIN crime_charges USING (crime_id)
    GROUP BY (FIRST, LAST)
    HAVING COUNT(Criminal_ID)<(SELECT AVG(COUNT(Criminal_ID))
    FROM crimes JOIN criminals USING (Criminal_ID)
    GROUP BY Criminal_ID)
    ORDER BY FIRST, LAST;
END IF;
close qry_lvl;
END;    
/ 

Answer 1

看起来您编写的代码应该被删除，以便您可以重新开始。

• 您开始声明游标，但从未完成
• 您没有声明任何游标变量来存储游标的值
  • 无论如何，您宁愿切换到光标 FOR 循环，因为它更易于使用
• 您要进入...什么？
• 没有end loop
• 您声明了 IN 和 OUT 参数，但从未使用过其中任何一个
• IF 中有一堆select 语句，几乎都返回不同的数据集。此外，其中任何一个都没有into 子句。 PL/SQL 需要它，因此您必须声明相当多的局部变量
• 错字，错字，错字……是chioce还是choice？
• column ... heading days 应该做什么？听起来像是与 SQL*Plus 相关的东西

---

也许您实际上想要使用 refcursors。这是一个基于 Scott 模式的简单示例。根据部门编号，我返回不同的数据集。

样本数据：

SQL> SELECT * FROM dept;

    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

过程（有点模拟您尝试做的事情）：

SQL> CREATE OR REPLACE PROCEDURE p_test (par_deptno  IN     NUMBER,
  2                                      par_rc         OUT SYS_REFCURSOR)
  3  IS
  4     l_dname  dept.dname%TYPE;
  5  BEGIN
  6     SELECT dname
  7       INTO l_dname
  8       FROM dept
  9      WHERE deptno = par_deptno;
 10
 11     IF l_dname = 'ACCOUNTING'
 12     THEN
 13        OPEN par_rc FOR SELECT d.dname, e.ename, e.job
 14                          FROM dept d
 15                               JOIN emp e
 16                                  ON     e.deptno = d.deptno
 17                                     AND d.deptno = par_deptno;
 18     ELSIF l_dname = 'SALES'
 19     THEN
 20        OPEN par_rc FOR SELECT e.ename, e.job, e.sal
 21                          FROM emp e
 22                         WHERE e.job = 'SALESMAN';
 23     END IF;
 24  END;
 25  /

Procedure created.

测试：

SQL> var l_rc refcursor
SQL> exec p_test(10, :l_rc);

PL/SQL procedure successfully completed.

SQL> print :l_rc

DNAME          ENAME      JOB
-------------- ---------- ---------
ACCOUNTING     CLARK      MANAGER
ACCOUNTING     KING       PRESIDENT
ACCOUNTING     MILLER     CLERK

SQL> exec p_test(30, :l_rc);

PL/SQL procedure successfully completed.

SQL> print :l_rc

ENAME      JOB              SAL
---------- --------- ----------
ALLEN      SALESMAN        1600
WARD       SALESMAN        1250
MARTIN     SALESMAN        1250
TURNER     SALESMAN        1500

SQL>

---

请阅读一些基本的 PL/SQL 文档，您不能开始编写自己的语法和编写代码。这是Oracle 12c PL/SQL Language Reference。阅读它需要一些时间，但是 - 至少 - 你会知道自己在做什么（我希望如此）。