我可以更具体地使用SQL排序吗？

Question

我有以下SQL查询：

SELECT  w.financial_year ,
        ISNULL(e.entity_name, 'Entity code ' + CAST(w.integer_1 AS VARCHAR) + ' is not available on the entity table. Please add.') ,
        COUNT(w.form_guid)
FROM    portal.workflow AS w
        LEFT OUTER JOIN property.entity AS e -- MS: Do not make inner join! Left outer join allows for exceptions to this case to be handled. Important as source data doesn't use property.entity
            ON w.integer_1 = e.entity_id
GROUP BY
        w.financial_year ,
        w.integer_1 ,
        e.entity_name
ORDER BY
        w.financial_year , e.entity_name

根据我的排序，我想展示e.entity_name首先为空的情况，然后按字母顺序对列的其余部分进行排序。这样的事情是否可能？

Answer 1

当然，

  SELECT w.financial_year,
    ISNULL(e.entity_name, 'Entity code ' + CAST(w.integer_1 AS VARCHAR) + 
        ' is not available on the entity table. Please add.') ,
    COUNT(w.form_guid)
  FROM portal.workflow AS w
     LEFT JOIN property.entity AS e
         ON w.integer_1 = e.entity_id
  GROUP BY case When e.entity_name Is Null Then 0 Else 1 End,
        w.financial_year, w.integer_1, e.entity_name
  ORDER BY case When e.entity_name Is Null Then 0 Else 1 End, 
      w.financial_year, e.entity_name

Answer 2

你可以试试这个：

ORDER BY
        CASE WHEN e.entity_name IS NULL 
             THEN 0 
             ELSE w.financial_year END 
        ,e.entity_name

See this SQLFiddle

Answer 3

在ORDER BY子句中使用NULLS FIRST或NULLS LAST，如下所示：

SELECT  w.financial_year ,
        ISNULL(e.entity_name, 'Entity code ' + CAST(w.integer_1 AS VARCHAR) + ' is not available on the entity table. Please add.') ,
        COUNT(w.form_guid)
FROM    portal.workflow AS w
        LEFT OUTER JOIN property.entity AS e -- MS: Do not make inner join! Left outer join allows for exceptions to this case to be handled. Important as source data doesn't use property.entity
            ON w.integer_1 = e.entity_id
GROUP BY
        w.financial_year ,
        w.integer_1 ,
        e.entity_name
ORDER BY
        w.financial_year , e.entity_name NULLS FIRST