How to transfer Oracle (+) operator with joins to Spark SQL? - sql

Question

I have a part of code in Oracle as this:
SELECT
t1.col1,
t1.col2,
t2.col1,
t2,col2
FROM
t1,
t2
WHERE
t1.col1 <> 121
AND t1.col1 = t2.col1(+)
AND t1.col2 = t2.col2(+)
AND 'ABC' = t2.col3(+)
How to transfer it to Spark SQL assuming tables (t1 and t2) are already registered?
Thanks.

Answer 1

(+) is the old Oracle outer join operator. It was used like this (Scott's sample schema; there are no employees in department 40 so - if you want to display it, you have to use outer join):
SQL> select d.deptno, d.dname, e.ename
2 from emp e,
3 dept d
4 where d.deptno = e.deptno (+) --> outer join
5 order by d.deptno, e.ename;
DEPTNO DNAME ENAME
---------- -------------- ----------
10 ACCOUNTING CLARK
10 ACCOUNTING KING
10 ACCOUNTING MILLER
20 RESEARCH ADAMS
20 RESEARCH FORD
20 RESEARCH JONES
20 RESEARCH SCOTT
20 RESEARCH SMITH
30 SALES ALLEN
30 SALES BLAKE
30 SALES JAMES
30 SALES MARTIN
30 SALES TURNER
30 SALES WARD
40 OPERATIONS --> department with no employees
15 rows selected.
If Spark SQL supports modern ANSI syntax, then the above code can be rewritten to
SQL> select d.deptno, d.dname, e.ename
2 from dept d left join emp e on e.deptno = d.deptno --> outer join
3 order by d.deptno, e.ename;
DEPTNO DNAME ENAME
---------- -------------- ----------
10 ACCOUNTING CLARK
10 ACCOUNTING KING
10 ACCOUNTING MILLER
20 RESEARCH ADAMS
20 RESEARCH FORD
20 RESEARCH JONES
20 RESEARCH SCOTT
20 RESEARCH SMITH
30 SALES ALLEN
30 SALES BLAKE
30 SALES JAMES
30 SALES MARTIN
30 SALES TURNER
30 SALES WARD
40 OPERATIONS --> department with no employees
15 rows selected.
SQL>
See if it helps.

Answer 2

I do not see the point of joining t1 and t2:
SELECT
t1.col1,
t1.col2
FROM
t1
WHERE
t1.col1 <> 121