MIN function behavior changed on Oracle databases after SAS Upgrade to 9.4M7 - oracle

Question

I have a program that has been working for years. Today, we upgraded from SAS 9.4M3 to 9.4M7.
proc setinit
Current version: 9.04.01M7P080520
Since then, I am not able to get the same results as before the upgrade.
Please note that I am querying on Oracle databases directly.
Trying to replicate the issue with a minimal, reproducible SAS table example, I found that the issue disappear when querying on a SAS table instead of on Oracle databases.
Let's say I have the following dataset:
data have;
infile datalines delimiter="|";
input name :$8. id $1. value :$8. t1 :$10.;
datalines;
Joe|A|TLO
Joe|B|IKSK
Joe|C|Yes
;
Using the temporary table:
proc sql;
create table want as
select name,
min(case when id = "A" then value else "" end) as A length 8
from have
group by name;
quit;
Results:
name A
Joe TLO
However, when running the very same query on the oracle database directly I get a missing value instead:
proc sql;
create table want as
select name,
min(case when id = "A" then value else "" end) as A length 8
from have_oracle
group by name;
quit;
name A
Joe
As per documentation, the min() function is behaving properly when used on the SAS table
The MIN function returns a missing value (.) only if all arguments are missing.
I believe this happens when Oracle don't understand the function that SAS is passing it - the min functions in SAS and Oracle are very different and the equivalent in SAS would be LEAST().
So my guess is that the upgrade messed up how is translates the SAS min function to Oracle, but it remains a guess. Does anyone ran into this type of behavior?
EDIT: #Richard's comment
options sastrace=',,,d' sastraceloc=saslog nostsuffix;
proc sql;
create table want as
select t1.name,
min(case when id = 'A' then value else "" end) as A length 8
from oracle_db.names t1 inner join oracle_db.ids t2 on (t1.tid = t2.tid)
group by t1.name;
ORACLE_26: Prepared: on connection 0
SELECT * FROM NAMES
ORACLE_27: Prepared: on connection 1
SELECT UI.INDEX_NAME, UIC.COLUMN_NAME FROM USER_INDEXES UI,USER_IND_COLUMNS UIC WHERE UI.TABLE_NAME='NAMES' AND
UIC.TABLE_NAME='NAMES' AND UI.INDEX_NAME=UIC.INDEX_NAME
ORACLE_28: Executed: on connection 1
SELECT statement ORACLE_27
ORACLE_29: Prepared: on connection 0
SELECT * FROM IDS
ORACLE_30: Prepared: on connection 1
SELECT UI.INDEX_NAME, UIC.COLUMN_NAME FROM USER_INDEXES UI,USER_IND_COLUMNS UIC WHERE UI.TABLE_NAME='IDS' AND
UIC.TABLE_NAME='IDS' AND UI.INDEX_NAME=UIC.INDEX_NAME
ORACLE_31: Executed: on connection 1
SELECT statement ORACLE_30
ORACLE_32: Prepared: on connection 0
select t1."NAME", MIN(case when t2."ID" = 'A' then t1."VALUE" else ' ' end) as A from
NAMES t1 inner join IDS t2 on t1."TID" = t2."TID" group by t1."NAME"
ORACLE_33: Executed: on connection 0
SELECT statement ORACLE_32
ACCESS ENGINE: SQL statement was passed to the DBMS for fetching data.
NOTE: Table WORK.SELECTED_ATTR created, with 1 row and 2 columns.
! quit;
NOTE: PROCEDURE SQL used (Total process time):
real time 0.34 seconds
cpu time 0.09 seconds

Answer 1

Use the SASTRACE= system option to log SQL statements sent to the DBMS.
options SASTRACE=',,,d';
will provide the most detailed logging.
From the prepared statement you can see why you are getting a blank from the Oracle query.
select
t1."NAME"
, MIN ( case
when t2."ID" = 'A' then t1."VALUE"
else ' '
end
) as A
from
NAMES t1 inner join IDS t2 on t1."TID" = t2."TID"
group by
t1."NAME"
The SQL MIN () aggregate function will exclude null values from consideration.
In SAS SQL, a blank value is also interpreted as null.
In SAS your SQL query returns the min non-null value TLO
In Oracle transformed query, the SAS blank '' is transformed to ' ' a single blank character, which is not-null, and thus ' ' < 'TLO' and you get the blank result.
The actual MIN you want to force in Oracle is min(case when id = "A" then value else null end) which #Tom has shown is possible by omitting the else clause.
The only way to see the actual difference is to run the query with trace in the prior SAS version, or if lucky, see the explanation in the (ignored by many) "What's New" documents.

Answer 2

Why are you using ' ' or '' as the ELSE value? Perhaps Oracle is treating a string with blanks in it differently than a null string.
Why not use null in the ELSE clause?
or just leave off the ELSE clause and let it default to null?
libname mylib oracle .... ;
proc sql;
create table want as
select name
, min(case when id = "A" then value else null end) as A length 8
from mylib.have_oracle
group by name
;
quit;
Also try running the Oracle code yourself, instead of using implicit pass thru.
proc sql;
connect to oracle ..... ;
create table want as
select * from connection to oracle
(
select name,
min(case when id = "A" then value else null end) as A length 8
from have_oracle
group by name
)
;
quit;

Answer 3

When I try to reproduce this in Oracle I get the result you are looking for so I suspect it has something to do with SAS (which I'm not familiar with).
with t as (
select 'Joe' name, 'A' id, 'TLO' value from dual union all
select 'Joe' name, 'B' id, 'IKSK' value from dual union all
select 'Joe' name, 'C' id, 'Yes' value from dual
)
select name
, min(case when id = 'A' then value else '' end) as a
from t
group by name;
NAME A
---- ----
Joe TLO
Unrelated, if you are only interested in id = 'A' then a better query would be:
select name
, min(value) as a
from t
where id = 'A'
group by name;