ORA-00979 not a group by expression
I am getting ORA-00979 with the following query:
SELECT cr.review_sk, cr.cs_sk, cr.full_name,
tolist(to_char(cf.fact_date, 'mm/dd/yyyy')) "appt",
cs.cs_id, cr.tracking_number
from review cr, cs, fact cf
where cr.cs_sk = cs.cs_sk
and UPPER(cs.cs_id) like '%' || UPPER(i_cs_id) || '%'
and row_delete_date_time is null
and cr.review_sk = cf.review_wk (+)
and cr.fact_type_code (+) = 183050
GROUP BY cr.review_sk, cr.cs_sk, cf.fact_date, cr.tracking_number
ORDER BY cs.cs_id, cr.full_name;
I couldn't find any examples that had both GROUP BY and ORDER BY clauses in the same query. I tried removing each field from the group by one at a time, but am still getting the same error.
You must put all columns of the SELECT
in the GROUP BY
or use functions on them which compress the results to a single value (like MIN
, MAX
or SUM
).
A simple example to understand why this happens: Imagine you have a database like this:
FOO BAR
0 A
0 B
and you run SELECT * FROM table GROUP BY foo
. This means the database must return a single row as result with the first column 0
to fulfill the GROUP BY
but there are now two values of bar
to chose from. Which result would you expect - A
or B
? Or should the database return more than one row, violating the contract of GROUP BY
?
Include in the GROUP BY
clause all SELECT
expressions that are not group function arguments.
Too bad Oracle has limitations like these. Sure, the result for a column not in the GROUP BY would be random, but sometimes you want that. Silly Oracle, you can do this in MySQL/MSSQL.
BUT there is a work around for Oracle:
While the following line does not work
SELECT unique_id_col, COUNT(1) AS cnt FROM yourTable GROUP BY col_A;
You can trick Oracle with some 0's like the following, to keep your column in scope, but not group by it (assuming these are numbers, otherwise use CONCAT)
SELECT MAX(unique_id_col) AS unique_id_col, COUNT(1) AS cnt
FROM yourTable GROUP BY col_A, (unique_id_col*0 + col_A);