Help Center/ GaussDB(DWS)/ Tool Guide/ DSC/ SQL Syntax Migration Reference/ Teradata Syntax Migration/ Data Manipulation Language (DML)/ SELECT/ Extended Group By Clause
Updated on 2024-07-19 GMT+08:00
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Extended Group By Clause

The GROUP BY clause can be specified if you want the database to group the selected rows based on the value of expr(s). If this clause contains CUBE, ROLLUP or GROUPING SETS extensions, then the database produces super-aggregate groupings in addition to the regular groupings. These features are not available in GaussDB(DWS), but similar functions can be enabled using the UNION ALL operator.

Use the extendedGroupByClause configuration parameter to configure migration of the extended GROUP BY clause.

Input: Extended Group By Clause - CUBE

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SELECT expr1 AS alias1
      , expr2 AS alias2 
      , expr3 AS alias3
      , MAX( expr4 ), ...
   FROM tab1 T1 INNER JOIN tab2 T2
     ON T1.c1 = T2.c2 ...
    AND T3.c5 = '010'
    AND ...
  WHERE T1.c7 = '000'
    AND ...
 HAVING alias1 <> 'IC'
         AND alias2 <> 'IC'
         AND alias3 <> ''
  GROUP BY 1, 2, 3 ;

Output

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SELECT
          expr1 AS "alias1"
          ,expr2 AS "alias2"
          ,expr3 AS "alias3"
          ,MAX( expr4 )
          ,...
     FROM
          tab1 T1 INNER JOIN tab2 T2
               ON T1.c1 = T2.c2 ...
          AND T3.c5 = '010'
          AND ...
     WHERE
          T1.c7 = '000'
          AND ...
     GROUP BY
          1 ,2 ,3
     HAVING
          alias1 <> 'IC'
          AND alias2 <> 'IC'
          AND alias3 <> '' ;

Input: Extended Group By Clause - ROLLUP

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SELECT d.dname, e.job, MAX(e.sal)
  FROM emp e RIGHT OUTER JOIN dept d
    ON e.deptno=d.deptno
WHERE e.job IS NOT NULL
GROUP BY ROLLUP (d.dname, e.job);

Output

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SELECT dname, job, ColumnAlias1
  FROM ( SELECT MAX(e.sal) AS ColumnAlias1, d.dname, e.job
           FROM emp e RIGHT OUTER JOIN dept d
             ON e.deptno = d.deptno
          WHERE e.job IS NOT NULL
          GROUP BY d.dname ,e.job
          UNION ALL 
         SELECT MAX(e.sal) AS ColumnAlias1, d.dname, NULL AS                    
                 job
           FROM emp e RIGHT OUTER JOIN dept d
             ON e.deptno = d.deptno
          WHERE e.job IS NOT NULL
          GROUP BY d.dname
          UNION ALL 
         SELECT MAX( e.sal ) AS ColumnAlias1, NULL AS dname,  
                     NULL AS job
           FROM emp e RIGHT OUTER JOIN dept d
             ON e.deptno = d.deptno
          WHERE e.job IS NOT NULL
        );

Input: Extended Group By Clause - GROUPING SETS

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SELECT d.dname, e.job, MAX(e.sal)
FROM emp e RIGHT OUTER JOIN dept d
ON e.deptno=d.deptno
WHERE e.job IS NOT NULL
GROUP BY GROUPING SETS(d.dname, e.job);

Output

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SELECT dname, job, ColumnAlias1
  FROM ( SELECT MAX(e.sal) AS ColumnAlias1
              , d.dname, NULL AS job
           FROM emp e RIGHT OUTER JOIN dept d
             ON e.deptno = d.deptno
          WHERE e.job IS NOT NULL
          GROUP BY d.dname
          UNION ALL 
         SELECT MAX(e.sal) AS ColumnAlias1
              , NULL AS dname, e.job
           FROM emp e RIGHT OUTER JOIN dept d
             ON e.deptno = d.deptno
          WHERE e.job IS NOT NULL
          GROUP BY e.job
        );
Parent topic: SELECT