DB2 sql查询运行

Question

Trying to run some query for DB2, but get no results.

SELECT APPLICATION_ID, 
       CLIENT_WRKSTNNAME 
  FROM TABLE(MON_GET_CONNECTION(cast(NULL as bigint), -2)) AS t 
 WHERE APPLICATION_ID IN (SELECT ''''||APPLICATION_ID||'''' 
                            FROM SYSIBM.SYSDUMMY1)

The problem is in subquery in WHERE clause. If I'll run only the

SELECT ''''||APPLICATION_ID||'''' 
  FROM SYSIBM.SYSDUMMY1 

part and copy/paste the result into the big query - I would get needed result. Result of sub-query looks like this: '92.81.111.13.51632.13022516453' , it must be String/varchar.

What am I doing wrong?

Answer 1

Your query does not make sense. Here is the version with table aliases:

SELECT t.APPLICATION_ID, t.CLIENT_WRKSTNNAME 
  FROM TABLE(MON_GET_CONNECTION(cast(NULL as bigint), -2)) AS t 
 WHERE t.APPLICATION_ID IN (SELECT ''''||t.APPLICATION_ID||'''' FROM SYSIBM.SYSDUMMY1);

One possibility is that the field APPLICATION_ID is being compared to itself, with quotes. SYSIBM.SYSDUMMY1 does not have a column called APPLICATION_ID . So, this query is equivalent to:

SELECT t.APPLICATION_ID, t.CLIENT_WRKSTNNAME 
  FROM TABLE(MON_GET_CONNECTION(cast(NULL as bigint), -2)) AS t 
 WHERE t.APPLICATION_ID = ''''||t.APPLICATION_ID||'''' ;

Another possibility is that APPLICATION_ID is a variable. In that case, you should name the variable something like v_APPLICATION_ID so it is not confused with the column name.

It looks like you want something like:

 WHERE '.'||t.APPLICATION_ID||'.' like '%.'||v_APPLICATION_IDS||'.%' ;

This is assuming the list in v_APPLICATION_IDS is separated by periods. Usually, it would be separated by commas and you would use ',' instead of '.' .

Answer 2

WITH s AS (SELECT APPLICATION_ID AS application_id FROM SYSIBM.SYSDUMMY1)
SELECT CLIENT_WRKSTNNAME
FROM TABLE(MON_GET_CONNECTION(cast(NULL as bigint), -2)) AS t
INNER join s as s on s.application_id=t.APPLICATION_ID