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CREATE TABLE test (col1 INT, col2 INT, col3 INT);
✓
INSERT INTO test VALUES
(1,2,3), (1,4,5), (3,2,1);
✓
SELECT * FROM test;
| col1 | col2 | col3 |
|---|---|---|
| 1 | 2 | 3 |
| 1 | 4 | 5 |
| 3 | 2 | 1 |
SELECT CASE WHEN SUM(CASE WHEN col1 = 1 THEN 1 END) = 1 THEN 'col1'
WHEN SUM(CASE WHEN col2 = 1 THEN 1 END) = 1 THEN 'col2'
WHEN SUM(CASE WHEN col3 = 1 THEN 1 END) = 1 THEN 'col3'
ELSE 'none'
END where_only_one_1
FROM test;
| where_only_one_1 |
|---|
| col3 |