SELECT COLUMN_NAME FROM ( SELECT COLUMN_NAME, ROW_NUMBER() OVER (PARTITION BY COLUMN_NAME ORDER BY CASE WHEN val IS NULL THEN 1 ELSE 0 END, val) AS row FROM ( SELECT COLUMN_NAME, CASE WHEN ROW_NUMBER() OVER (PARTITION BY COLUMN_NAME ORDER BY (SELECT NULL)) = 1 THEN val ELSE NULL END AS val FROM your_table ) t ) t2 WHERE row = 1;
注:
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