Ambiguous column name error

Question

When executing the following (complete) SQL query on Microsoft SQL Server 2000:

SELECT B.ARTIFACTTNS, B.ARTIFACTNAME, B.ARTIFACTTYPE, B.INITIALBYTES, B.TIMES         


        

Answer 1

If that's the exact query you're running, I have no idea why it would find anything ambiguous.

I wrote what I think is an equivalent query and ran it in my database (Oracle) with no problem.

EDIT Adding exact output of a new experiment in Oracle. The query executed in this experiment is the exact query given by the OP, with the table name filled in. NO OTHER CHANGES. There's nothing ambiguous in this query. So, either that is not the exact query that is being executed, or SQL Server has a parser bug.

SQL> create table props (pname varchar2(100),
  2                       pvalue varchar2(100),
  3                       artifacttype number,
  4                       artifacttns number,
  5                       artifactname number);

Table created.

SQL> SELECT      
  2    DISTINCT A.ARTIFACTTYPE, A.ARTIFACTTNS, A.ARTIFACTNAME
  3  FROM
  4   (SELECT DISTINCT 
  5      ARTIFACTTYPE, 
  6      ARTIFACTTNS, 
  7      ARTIFACTNAME 
  8    FROM props 
  9    WHERE PNAME = 'AcmeSystemName' 
 10        AND PVALUE = 'MyRuleGroup' 
 11    UNION 
 12    SELECT DISTINCT 
 13      ARTIFACTTYPE, 
 14      ARTIFACTTNS, 
 15      ARTIFACTNAME 
 16    FROM props
 17    WHERE PNAME = 'AcmeSystemDisplayName' 
 18        AND PVALUE = 'MyRuleGroup') A, 
 19  (SELECT DISTINCT 
 20      ARTIFACTTYPE, 
 21      ARTIFACTTNS, 
 22      ARTIFACTNAME 
 23   FROM props 
 24   WHERE PNAME = 'AcmeSystemTargetNameSpace' 
 25      AND PVALUE = 'http://mymodule') B
 26  WHERE A.ARTIFACTTYPE = B.ARTIFACTTYPE 
 27      AND A.ARTIFACTTNS = B.ARTIFACTTNS 
 28      AND A.ARTIFACTNAME = B.ARTIFACTNAME
 29  /

no rows selected

End Edit

My suggestion for getting around the error is to give the table in each select clause a unique alias and qualify all column references. Like this:

SELECT
  DISTINCT A.ARTIFACTTYPE, A.ARTIFACTTNS, A.ARTIFACTNAME
FROM
 (SELECT DISTINCT 
    P1.ARTIFACTTYPE, 
    P1.ARTIFACTTNS, 
    P1.ARTIFACTNAME 
  FROM {PROPERTIES_TABLE_NAME} P1
  WHERE PNAME = 'AcmeSystemName' 
      AND PVALUE = 'MyRuleGroup' 
  UNION 
  SELECT DISTINCT 
    P2.ARTIFACTTYPE, 
    P2.ARTIFACTTNS, 
    P2.ARTIFACTNAME 
  FROM {PROPERTIES_TABLE_NAME} P2
  WHERE PNAME = 'AcmeSystemDisplayName' 
      AND PVALUE = 'MyRuleGroup') A, 
(SELECT DISTINCT 
    P3.ARTIFACTTYPE, 
    P3.ARTIFACTTNS, 
    P3.ARTIFACTNAME 
 FROM {PROPERTIES_TABLE_NAME} P3
 WHERE PNAME = 'AcmeSystemTargetNameSpace' 
    AND PVALUE = 'http://mymodule') B
WHERE A.ARTIFACTTYPE = B.ARTIFACTTYPE 
    AND A.ARTIFACTTNS = B.ARTIFACTTNS 
    AND A.ARTIFACTNAME = B.ARTIFACTNAME