如果Column1不为null,则按Column1排序,否则按Column2排序

Question

有没有办法在sql中组合ORDER BY,IS NULL以便我可以按列排序,如果列不为null,但如果它为null,则按另一列排序？

Answer 1

就像是:

ORDER BY CASE 
    WHEN Column1 IS NOT NULL THEN Column1
    ELSE Column2
END

与写作相同:

ORDER BY COALESCE(Column1, Column2)

Answer 2

试试这个

  ORDER BY COALESCE(fieldA, fieldB);