The Oracle ANSI SQL Join syntax is shown below.

WITH table_a AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION 
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 25 idx, 'idx_25' idx_desc FROM DUAL UNION
 SELECT 30 idx, 'idx_30' idx_desc FROM DUAL),
table_b AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 35 idx, 'idx_35' idx_desc FROM DUAL UNION
 SELECT 40 idx, 'idx_40' idx_desc FROM DUAL)
SELECT  ta.idx,  ta.idx_desc
FROM table_a ta INNER JOIN table_b tb
  ON  ta.idx = tb.idx;



Oracle ANSI Inner Join Query Output

WITH table_a AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 25 idx, 'idx_25' idx_desc FROM DUAL UNION
 SELECT 30 idx, 'idx_30' idx_desc FROM DUAL),
table_b AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 35 idx, 'idx_35' idx_desc FROM DUAL UNION
 SELECT 40 idx, 'idx_40' idx_desc FROM DUAL)
SELECT  ta.idx,  ta.idx_desc
FROM table_a ta JOIN table_b tb  ON (ta.idx = tb.idx);

Oracle ANSI Join On Query Output

WITH table_a AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 25 idx, 'idx_25' idx_desc FROM DUAL UNION
 SELECT 30 idx, 'idx_30' idx_desc FROM DUAL),
table_b AS
(SELECT 10 idx, 'idx_10' idx_desc FROM DUAL UNION
 SELECT 15 idx, 'idx_15' idx_desc FROM DUAL UNION
 SELECT 20 idx, 'idx_20' idx_desc FROM DUAL UNION
 SELECT 35 idx, 'idx_35' idx_desc FROM DUAL UNION
 SELECT 40 idx, 'idx_40' idx_desc FROM DUAL)
SELECT * FROM table_a ta JOIN table_b tb USING (idx);

Oracle ANSI Join Using Query Output