SQL FETCH,游标和RPG

Question

我不确定我的代码有什么问题,我正在尝试创建一个while循环,它将使用SQL中声明的游标获取字段(代码)中的下一个字符.目标是通过循环获得下一个匹配的字符.然后我想在循环结束时返回结果.如果没有完全匹配,目标是与代码进行部分匹配.我之前从未使用过游标,因此我尝试尽可能多地学习使用fetch和游标.

   EXEC SQL
   SELECT field FROM file
   WHERE  field = :code

   UNION

   DECLARE UserInput CURSOR FOR
   SELECT field FROM file
   WHERE  field LIKE '%' || :code || '%'
   ORDER BY field ASC

   OPEN UserInput
   FETCH NEXT FROM UserInput
   BEGIN
       DO WHILE <> %EOF 
             FETCH NEXT FROM UserInput
   END
   CLOSE UserInput
   DEALLOCATE UserInput;

Answer 1

哇......这里错了很多......快看一眼......

1. 你试图将光标声明在错误的位置.
2. %EOF() 使用RPG记录级别访问,您需要检查SQLCODE或SQLSTATE
3. FETCH OPEN 都是SQL语句,需要在一个 EXEC SQL
4. DEALLOCATE 不需要
5. 需要FETCH将游标中的行转换为RPG变量

看看这段代码:

EXEC SQL                                            
  DECLARE UserInput CURSOR FOR                      
    SELECT field FROM file                          
    WHERE  field = :code                            
    UNION                                           
    SELECT field FROM file                          
    WHERE  field LIKE '%' || :code || '%'           
    ORDER BY field ASC;                             
EXEC SQL                                            
  OPEN UserInput;                                   
--really should check SQLSTATE here too!            

EXEC SQL                                            
  FETCH NEXT FROM UserInput INTO :MyRpgVar;         

Dow SQLSTATE = '00000';                              
   --note 00000 = no errors or warning              
   --     02000 = no data                           
   <do somthing?>                                   
   EXEC SQL                                         
      FETCH NEXT FROM UserInput INTO :MyRpgVar;     
ENDDO;                                              

EXEC SQL                                            
  CLOSE UserInput; 

我建议你阅读嵌入式SQL编程参考的RPGLE部分.