来自存储过程的 DISTINCT 值答案

【问题标题】：DISTINCT value from stored procedure来自存储过程的 DISTINCT 值
【发布时间】：2016-09-07 16:15:45
【问题描述】：

CREATE PROCEDURE [dbo].[GetIdleCustomerlist](
@num_months Int
)

AS
BEGIN

SELECT DISTINCT
    cust.cust_code as cust_code ,
    cust.name as cust_name,
    MAX (invoice.created_date) as Last_invoice_date             

    FROM [dbo].[customer] cust LEFT JOIN  [dbo].[crm_invoice_header] invoice on cust.cust_code = invoice.cust_code

    GROUP BY cust.cust_code ,cust.name,invoice.created_date

    HAVING (( MAX (invoice.created_date)< DATEADD(MONTH, -@num_months ,GETDATE())) OR invoice.created_date IS NULL)

    ORDER BY CAST (cust.cust_code AS int) ASC

END

我想删除重复的客户代码，但 DISTINCT 关键字给了我这个错误。

消息 145，级别 15，状态 1，过程 GetIdleCustomerlist，第 21 行如果指定了 SELECT DISTINCT，则 ORDER BY 项必须出现在选择列表中。

【问题讨论】：

标签： sql sql-server stored-procedures

【解决方案1】：

试试这个版本的查询：

SELECT cust.cust_code as cust_code, cust.name as cust_name,
      MAX(invoice.created_date) as Last_invoice_date             
FROM [dbo].[customer] cust LEFT JOIN
     [dbo].[crm_invoice_header] invoice
     on cust.cust_code = invoice.cust_code
GROUP BY cust.cust_code, cust.name
HAVING (( MAX (invoice.created_date) < DATEADD(MONTH, -@num_months, GETDATE())) OR MAX(invoice.created_date) IS NULL)
ORDER BY CAST(cust.cust_code AS int) ASC;

distinct 不是必需的，您需要从GROUP BY 中删除日期。

【讨论】：

删除日期时，它给我错误“消息 8121，级别 16，状态 1，第 7 行列 'dbo.crm_invoice_header.created_date' 在 HAVING 子句中无效，因为它不包含在聚合函数或 GROUP BY 子句。"
@Amila 。 . .你只需要使用MAX(invoice.created_date)。

【解决方案2】：

删除DISTINCT并删除GROUP BY子句中的invoice.created_date：

SELECT
    cust.cust_code AS cust_code,
    cust.name AS cust_name,
    MAX(invoice.created_date) AS Last_invoice_date      
FROM dbo.customer cust
LEFT JOIN dbo.crm_invoice_header invoice
    ON cust.cust_code = invoice.cust_code
WHERE
    invoice.created_date < DATEADD(MONTH, -@num_months, GETDATE())
    OR invoice.created_date IS NULL
GROUP BY
    cust.cust_code, cust.name
ORDER BY
    ORDER BY CAST(cust.cust_code AS INT)

您也可以将HAVING中的条件移动到WHERE

【讨论】：