在Oracle查询中出现“ FROM”错误

Question

I'm getting this error on the below query. The query is to modify a constraint

SELECT 'EXEC DROP_CONSTRAINTS('RTK_TYUVOICE_SYSTEM','IOA_WRTYOICE');' FROM DUAL
                                                   *

ERROR at line 1:

ORA-00923: FROM keyword not found where expected

Please advise on how to overcome this when I execute the above query from sql/nolog

Answer 1

Either double quotes in the string

SELECT 'EXEC DROP_CONSTRAINTS(''RTK_TYUVOICE_SYSTEM'',''IOA_WRTYOICE'');' as txt FROM DUAL;

TXT                                                        
------------------------------------------------------------
EXEC DROP_CONSTRAINTS('RTK_TYUVOICE_SYSTEM','IOA_WRTYOICE'); 

or use the (from 10g) quoted string

SELECT q'[EXEC DROP_CONSTRAINTS('RTK_TYUVOICE_SYSTEM','IOA_WRTYOICE');]' as txt FROM DUAL;

TXT                                                        
------------------------------------------------------------
EXEC DROP_CONSTRAINTS('RTK_TYUVOICE_SYSTEM','IOA_WRTYOICE');

Answer 2

You are trying to modify a constraint using a statement I hope, and are not looking to just print your statement.

In that case, you need to make use of Execute Immediate statement, which helps to execute DDL statements on the fly in a procedure.

BEGIN
EXECUTE IMMEDIATE 'ALTER TABLE ANAL2 DROP CONSTRAINT SYS_C008611' ;
END;
/

Any valid DDL statement (like create, alter, drop etc) can be squeezed in the EXECUTE IMMEDIATE statement, using their correct syntactic formation.

Alternatively, you could just mention, if the given SQL is static, as

ALTER TABLE ANAL2 DROP CONSTRAINT SYS_C008611