Question

我遇到了一个SQL查询问题。如果已经存在相同的行，我需要插入一行。这就是我到目前为止所做的：

DECLARE
BEGIN
   FOR FOLDER_ROW IN (SELECT FOLDERID, USERID FROM DATA1.FOLDERS)
      LOOP                       
          IF NOT EXISTS (SELECT * FROM DATA1.FOLDER_USER WHERE FOLDER_ID = FOLDER_ROW.FOLDERID AND USER_ID = FOLDER_ROW.USERID) 
          INSERT INTO DATA1.FOLDER_USER (FOLDER_ID, USER_ID) VALUES (FOLDER_ROW.FOLDERID, FOLDER_ROW.USERID);
     END LOOP;
    COMMIT;
END;

我不太熟悉sql特别是不存在的语法所以当我执行时我得到以下错误：

ORA-06550：第37行，第11栏：PLS-00103：遇到符号   期待以下之一时“插入”：

然后和或

符号“then”代替“INSERT”继续。

ORA-06550: line 38, column 10:
PLS-00103: Encountered the symbol "LOOP" when expecting one of the following:

   if
ORA-06550: line 40, column 5:
PLS-00103: Encountered the symbol "end-of-file" when expecting one of the following:

   end not pragma final instantiable order overriding static
   member constructor map

Answer 1

在SQL中完成所有操作而不是上下文切换到PL / SQL：

INSERT INTO DATA1.FOLDERS
(folder_id,
 user_id)
SELECT f1.folder_id,
       f1.user_id
  FROM DATA1.FOLDERS f1
 WHERE NOT EXISTS (SELECT 1
                     FROM DATA1.FOLDERS f2
                    WHERE f1.folder_id = f2.folder_id
                      AND f1.user_id = f2.user_id);

Answer 2

更好的（特定于Oracle的？）解决方案可能是MERGE语句。

请参阅此处以获得一个很好的解释，例如：

http://www.oracle-base.com/articles/10g/MergeEnhancements10g.php

希望有所帮助。

Answer 3

您忘记了那么

IF condition THEN  
   ...
ELSE
    ...
END IF;

Answer 4

DECLARE
    N_COUNTS NUMBER;
BEGIN
    select count(ID) into N_COUNTS from TABLE_NAME where ID = 1;
    IF N_COUNTS=0 THEN
        INSERT QUERY....
    ELSE
        UPDATE QUERY....
    END IF;
END;

sql - 如果不存在则插入

4 个答案: