Oracle 21c

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CREATE TABLE table1 (account_id) AS
SELECT 123451 FROM DUAL UNION ALL
SELECT 456123 FROM DUAL UNION ALL
SELECT 876495 FROM DUAL
3 rows affected

CREATE TABLE table2 (account_id) AS
SELECT 943215 FROM DUAL UNION ALL
SELECT 876495 FROM DUAL
2 rows affected

CREATE TABLE table3 (account_id) AS
SELECT 456123 FROM DUAL UNION ALL
SELECT 876495 FROM DUAL
2 rows affected

SELECT COALESCE(t1.account_id, t2.account_id, t3.account_id) AS account_id,
       NVL2(t1.account_id, 1, 0) AS in_table1,
       NVL2(t2.account_id, 1, 0) AS in_table2,
       NVL2(t3.account_id, 1, 0) AS in_table3
FROM   table1 t1
       FULL OUTER JOIN table2 t2
       ON (t1.account_id = t2.account_id)
       FULL OUTER JOIN table3 t3
       ON (  t1.account_id = t3.account_id
          OR t2.account_id = t3.account_id)


ACCOUNT_ID
IN_TABLE1
IN_TABLE2
IN_TABLE3


123451
1
0
0

456123
1
0
1

876495
1
1
1

943215
0
1
0