Question

我有以下简单的功能，我试图使用动态查询的简单功能即sqlstatement（虽然在这个例子中我提到了简单的查询）

create or replace
FUNCTION test_simple_func ( testVal IN VARCHAR2)
RETURN number IS
   total number(2) := 0;
  DECLARE @sqlstatement VARCHAR(MAX);
 BEGIN 
  SET @sqlstatement = 'Select * from employee'; 
  select count(*) INTO total from employee;
    RETURN total;
 END;

我在这里没有弄错？

Answer 1

这是在Oracle版本中：

CREATE OR REPLACE FUNCTION test_simple_func(
        testVal IN VARCHAR2)
      RETURN NUMBER
    AS
      total NUMBER;
        sqlstatement VARCHAR2(4000);
    BEGIN

      sqlstatement := 'Select * from employee';
      SELECT COUNT(*)
      INTO total
      FROM employee;
      RETURN total;
    END;

如果您想用作动态查询，那么您需要使用EXECUTE immediate 比如EXECUTE immediate sqlstatement

Answer 2

与varchar限制为4000的SQL不同，PL / SQL的限制大约是32K

否则，PL / SQL函数中没有声明。 DECLARE用于Oracle中的匿名集团。

正确的合成器是

CREATE OR REPLACE
FUNCTION test_simple_func ( testVal IN VARCHAR2)
RETURN number IS
   total number(2) := 0;
   sqlstatement VARCHAR(32000);
BEGIN 
  sqlstatement := 'Select * from employee'; 
  select count(*) INTO total from employee;
    RETURN total;
END;

Answer 3

declare块应该在所有声明之前开始：

create or replace
FUNCTION test_simple_func ( testVal IN VARCHAR2)
RETURN number IS
DECLARE -- right place for declare
   total number(2) := 0;
   sqlstatement VARCHAR(4000);
BEGIN 
  SET sqlstatement = 'Select * from employee'; 
  select count(*) INTO total from employee;
    RETURN total;
END;

Answer 4

根据我的记忆，Oracle不支持VARCHAR（MAX）

Answer 5

这是执行动态查询的正确方法

CREATE OR REPLACE FUNCTION test_simple_func(
    testVal IN VARCHAR2)
  RETURN NUMBER
IS
  total NUMBER(10) := 0;
  sqlstatement CLOB;
BEGIN
  sqlstatement := 'Select count(*) from employee';
  --select count(*) INTO total from employee;
  EXECUTE immediate sqlstatement INTO total;
  RETURN total;
END;

ERROR PLS-00103：遇到符号“DECLARE”？

5 个答案: