如何声明变量并在同一个Oracle SQL脚本中使用它?

在SQL*PLUS脚本中有几种声明变量的方法。

第一种方法是使用var。将值分配给var的机制是使用exec调用:

SQL> var name varchar2(20)
SQL> exec :name := 'SALES'

PL/SQL procedure successfully completed.

SQL> select * from dept
  2  where dname = :name
  3  /

    DEPTNO DNAME          LOC
---------- -------------- -------------
        30 SALES          CHICAGO

SQL>

当我们想要调用一个具有out参数或函数的存储过程时,var特别有用。

另外,我们可以使用子交换变量。这些适用于交互模式:

SQL> accept p_dno prompt "Please enter Department number: " default 10
Please enter Department number: 20
SQL> select ename, sal
  2  from emp
  3  where deptno = &p_dno
  4  /
old   3: where deptno = &p_dno
new   3: where deptno = 20

ENAME             SAL
---------- ----------
CLARKE            800
ROBERTSON        2975
RIGBY            3000
KULASH           1100
GASPAROTTO       3000

SQL>

当我们编写一个调用其他脚本的脚本时,预先定义变量是很有用的:

SQL> def p_dno = 40
SQL> select ename, sal
  2  from emp
  3  where deptno = &p_dno
  4  /
old   3: where deptno = &p_dno
new   3: where deptno = 40

no rows selected

SQL>

最后是匿名PL/SQL块。如您所见,我们仍然可以交互地为声明的变量赋值:

SQL> set serveroutput on size unlimited
SQL> declare
  2      n pls_integer;
  3      l_sal number := 3500;
  4      l_dno number := &dno;
  5  begin
  6      select count(*)
  7      into n
  8      from emp
  9      where sal > l_sal
 10      and deptno = l_dno;
 11      dbms_output.put_line('top earners = '||to_char(n));
 12  end;
 13  /
Enter value for dno: 10
old   4:     l_dno number := &dno;
new   4:     l_dno number := 10;
top earners = 1

PL/SQL procedure successfully completed.

SQL>

如果是char变量,请尝试使用双引号:

DEFINE stupidvar = "'stupidvarcontent'";

或

DEFINE stupidvar = 'stupidvarcontent';

SELECT stupiddata  
FROM stupidtable  
WHERE stupidcolumn = '&stupidvar'

UPD:

SQL*Plus: Release 10.2.0.1.0 - Production on Wed Aug 25 17:13:26 2010

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

SQL> conn od/od@etalon
Connected.
SQL> define var = "'FL-208'";
SQL> select code from product where code = &var;
old   1: select code from product where code = &var
new   1: select code from product where code = 'FL-208'

CODE
---------------
FL-208

SQL> define var = 'FL-208';
SQL> select code from product where code = &var;
old   1: select code from product where code = &var
new   1: select code from product where code = FL-208
select code from product where code = FL-208
                                      *
ERROR at line 1:
ORA-06553: PLS-221: 'FL' is not a procedure or is undefined

在PL/SQL V.10中

关键字declare用于声明变量

DECLARE stupidvar varchar(20);

要分配一个值,可以在声明

DECLARE stupidvar varchar(20) := '12345678';

或者在你使用的变量中选择一些东西 INTO 语句,但是需要将语句包装在 BEGIN 和 END ,还需要确保只返回单个值,并且不要忘记分号。

所以完整的陈述如下:

DECLARE stupidvar varchar(20);
BEGIN
    SELECT stupid into stupidvar FROM stupiddata CC 
    WHERE stupidid = 2;
END;

您的变量只能在 开始 和 结束 因此,如果你想使用多个,你必须做多次 BEGIN END 包装材料

DECLARE stupidvar varchar(20);
BEGIN
    SELECT stupid into stupidvar FROM stupiddata CC 
    WHERE stupidid = 2;

    DECLARE evenmorestupidvar varchar(20);
    BEGIN
        SELECT evenmorestupid into evenmorestupidvar FROM evenmorestupiddata CCC 
        WHERE evenmorestupidid = 42;

        INSERT INTO newstupiddata (newstupidcolumn, newevenmorestupidstupidcolumn)
        SELECT stupidvar, evenmorestupidvar 
        FROM dual

    END;
END;

希望这能节省你一些时间

如果您想声明日期,然后在SQL开发人员中使用它。

DEFINE PROPp_START_DT = TO_DATE('01-SEP-1999')

SELECT * 
FROM proposal 
WHERE prop_start_dt = &PROPp_START_DT

问题是要在脚本中使用一个变量,这意味着它将在SQL*PLUS中使用。

问题是您遗漏了引号,Oracle无法将值解析为数字。

SQL> DEFINE num = 2018
SQL> SELECT &num AS your_num FROM dual;
old   1: SELECT &num AS your_num FROM dual
new   1: SELECT 2018 AS your_num FROM dual

  YOUR_NUM
----------
      2018

Elapsed: 00:00:00.01

由于自动类型转换(或它被称为什么),此示例工作正常。

如果您通过在SQL*PLUS中键入define进行检查,它将显示num变量是char。

SQL>define
DEFINE NUM             = "2018" (CHAR)

在这种情况下,这不是问题,因为如果字符串是一个有效的数字,Oracle可以处理从字符串到数字的解析。

当字符串不能解析为数字时,Oracle就不能处理它。

SQL> DEFINE num = 'Doh'
SQL> SELECT &num AS your_num FROM dual;
old   1: SELECT &num AS your_num FROM dual
new   1: SELECT Doh AS your_num FROM dual
SELECT Doh AS your_num FROM dual
       *
ERROR at line 1:
ORA-00904: "DOH": invalid identifier

有了引号,所以不要强制Oracle解析为数字,这样就可以了:

17:31:00 SQL> SELECT '&num' AS your_num FROM dual;
old   1: SELECT '&num' AS your_num FROM dual
new   1: SELECT 'Doh' AS your_num FROM dual

YOU
---
Doh

因此,要回答最初的问题,应该这样做:

SQL> DEFINE stupidvar = 'X'
SQL>
SQL> SELECT 'print stupidvar:' || '&stupidvar'
  2  FROM dual
  3  WHERE dummy = '&stupidvar';
old   1: SELECT 'print stupidvar:' || '&stupidvar'
new   1: SELECT 'print stupidvar:' || 'X'
old   3: WHERE dummy = '&stupidvar'
new   3: WHERE dummy = 'X'

'PRINTSTUPIDVAR:'
-----------------
print stupidvar:X

Elapsed: 00:00:00.00

通过使用 查询列值 .

这个 科尔 [NUM] 纽尔值 按字段名存储查询值的选项。

SQL> COLUMN stupid_column_name new_value stupid_var noprint
SQL> SELECT dummy || '.log' AS stupid_column_name
  2  FROM dual;

Elapsed: 00:00:00.00
SQL> SPOOL &stupid_var.
SQL> SELECT '&stupid_var' FROM DUAL;
old   1: SELECT '&stupid_var' FROM DUAL
new   1: SELECT 'X.log' FROM DUAL

X.LOG
-----
X.log

Elapsed: 00:00:00.00
SQL>SPOOL OFF;

如您所见,x.log值被设置为 笨拙的 变量,因此我们可以在当前目录中找到一个x.log文件,其中包含一些日志。

只是想添加 马塔斯 “回答。 也许这很明显,但我已经找了很长时间才发现 变量只能在开始端内部访问 构造,所以如果以后需要在某些代码中使用它,则需要 将此代码放入起始块中 .

注意这些 块可以嵌套 :

DECLARE x NUMBER;
  BEGIN
    SELECT PK INTO x FROM table1 WHERE col1 = 'test';

    DECLARE y NUMBER;
    BEGIN
    SELECT PK INTO y FROM table2 WHERE col2 = x;

    INSERT INTO table2 (col1, col2)
      SELECT y,'text'
      FROM dual
      WHERE exists(SELECT * FROM table2);
    COMMIT;
  END;
END;

这是你的答案:

DEFINE num := 1;       -- The semi-colon is needed for default values.
SELECT &num FROM dual;