SQL - 插入到表，如果在另一个表存在价值

Question

我试图让下面的SQL查询工作，但我得到一个错误，我的问题是：

我需要通过设置一个结果循环从选择语句（这部分是好的）。在每一行的循环内，我需要检查URL是否存在于tableA中。如果确实如此，则将映射插入到tableB中，否则将新行插入到tableC中。

这就是我所拥有的，但是当我尝试执行时，我得到一条与IF中的错误说ORA-06550：第8行，第15列：PLS-00103：遇到符号“SELECT”下面:( - +案例国防部新的无.....

DECLARE 
STANDARD_LINK_ID TABLEB.LINK_ID%type; 

BEGIN 
     FOR LINK_ROW IN (SELECT LINKTEXT, LINKURL, CORPID FROM OLD_DATA) 
     LOOP 
      IF (SELECT COUNT(URL) FROM TABLEA WHERE URL = LINK_ROW.LINKURL) = 1 
      THEN 
      SELECT LINKID INTO STANDARD_LINK_ID FROM TABLEA WHERE URL = LINK_ROW.URL; 
      INSERT INTO TABLEB(LINK_ID, CORP_ID) 
      VALUES (STANDARD_LINK_ID, LINK_ROW.CORPID); 
      ELSE 
      INSERT INTO TABLEB(LINK_ID, LINK_NAME, URL, CORP_ID) 
      VALUES (SEQ_LINK.NEXTVAL, LINK_ROW.LINKTEXT, LINK_ROW.LINKURL, 
           LINK_ROW.CORP_ID); 
      END IF;     
     END LOOP; 
    COMMIT; 
END; 

Answer 1

我见过它做这种方式，并不是用在条件

https://forums.oracle.com/forums/thread.jspa?threadID=177035

内嵌返回值的选择

DECLARE 
STANDARD_LINK_ID TABLEB.LINK_ID%type; 
DECLARE W_LINK_COUNT NUMBER (1,0); 

BEGIN 
     FOR LINK_ROW IN (SELECT LINKTEXT, LINKURL, CORPID FROM OLD_DATA) 
     LOOP 
      SELECT COUNT(URL) INTO W_LINK_COUNT FROM TABLEA WHERE URL = LINK_ROW.LINKURL; 
      IF W_LINK_COUNT = 1 
      THEN 
      SELECT LINKID INTO STANDARD_LINK_ID FROM TABLEA WHERE URL = LINK_ROW.URL; 
      INSERT INTO TABLEB(LINK_ID, CORP_ID) 
      VALUES (STANDARD_LINK_ID, LINK_ROW.CORPID); 
      ELSE 
      INSERT INTO TABLEB(LINK_ID, LINK_NAME, URL, CORP_ID) 
      VALUES (SEQ_LINK.NEXTVAL, LINK_ROW.LINKTEXT, LINK_ROW.LINKURL, 
           LINK_ROW.CORP_ID); 
      END IF;     
     END LOOP; 
    COMMIT; 
END; 

Answer 2

我怀疑你的陈述是罪魁祸首，因为你试图达到的目标应该是可能的。你可以请尝试以下代替：

DECLARE 
STANDARD_LINK_ID TABLEB.LINK_ID%type; 
URL_COUNT NUMBER(10); 

BEGIN 
     FOR LINK_ROW IN (SELECT LINKTEXT, LINKURL, CORPID FROM OLD_DATA) 
     LOOP 
      SELECT COUNT(URL) INTO URL_COUNT FROM TABLEA WHERE URL = LINK_ROW.LINKURL; 
      IF URL_COUNT = 1 THEN 
      SELECT LINKID INTO STANDARD_LINK_ID FROM TABLEA WHERE URL = LINK_ROW.URL; 
      INSERT INTO TABLEB(LINK_ID, CORP_ID) 
      VALUES (STANDARD_LINK_ID, LINK_ROW.CORPID); 
      ELSE 
      INSERT INTO TABLEB(LINK_ID, LINK_NAME, URL, CORP_ID) 
      VALUES (SEQ_LINK.NEXTVAL, LINK_ROW.LINKTEXT, LINK_ROW.LINKURL, 
           LINK_ROW.CORP_ID); 
      END IF;     
     END LOOP; 
    COMMIT; 
END; 

希望它可以帮助你找出问题所在。

Answer 3

我写它的真快，但我认为这两个查询将解决你的问题，而循环（这是比较慢，然后一次性插入）：

-- insert to tableb when exists in tablea 
insert into tableb(link_id, corp_id) 
select a.linkid, o.corpid 
from old_data o 
join tablea a on o.url = a.url 


-- insert to tablec when not exists in tablea 
insert into tablec(link_id, link_name, url, corp_id) 
select seq_link.nextval, o.linktext, o.linkurl, o.corp_id 
from old_data o 
where not exists(select 1 from tablea a where o.url = a.url) 

PS。你不忘记tablec在else？