Sql 如何获取ID级别的数据

我有一个名为ID_info的表，示例数据为：

Info_ID   Type  Desc
1         S     Secondary
1         V     Vertical
2         U     Uniform
3         I     Industry
3         F     First

所以我需要一个列，告诉我不同的ID。计数的第一行应为数字，后续行应为空，因此我的输出应为：

   Info_ID   Type  Desc        Count_Info_ID
    1         S     Secondary   2
    1         V     Vertical    NULL
    2         U     Uniform     1
    3         I     Industry    2
    3         F     First       NULL

---

如果顺序不重要，那么应该这样做：

;WITH CTE AS
(
    SELECT  *, 
            COUNT(*) OVER(PARTITION BY Info_ID) Count_Info_ID, 
            ROW_NUMBER() OVER(PARTITION BY Info_ID ORDER BY Info_ID) RN
    FROM YourTable
)
SELECT  Info_ID,
        [Type],
        [Desc],
        CASE WHEN RN = 1 THEN Count_Info_ID END Count_Info_ID
FROM CTE

让你试试

结果是：

╔═════════╦══════╦═══════════╦═══════════════╗
║ Info_ID ║ Type ║   Desc    ║ Count_Info_ID ║
╠═════════╬══════╬═══════════╬═══════════════╣
║       1 ║ S    ║ Secondary ║ 2             ║
║       1 ║ V    ║ Vertical  ║ NULL          ║
║       2 ║ U    ║ Uniform   ║ 1             ║
║       3 ║ I    ║ Industry  ║ 2             ║
║       3 ║ F    ║ First     ║ NULL          ║
╚═════════╩══════╩═══════════╩═══════════════╝

---

如果顺序不重要，那么应该这样做：

;WITH CTE AS
(
    SELECT  *, 
            COUNT(*) OVER(PARTITION BY Info_ID) Count_Info_ID, 
            ROW_NUMBER() OVER(PARTITION BY Info_ID ORDER BY Info_ID) RN
    FROM YourTable
)
SELECT  Info_ID,
        [Type],
        [Desc],
        CASE WHEN RN = 1 THEN Count_Info_ID END Count_Info_ID
FROM CTE

让你试试

结果是：

╔═════════╦══════╦═══════════╦═══════════════╗
║ Info_ID ║ Type ║   Desc    ║ Count_Info_ID ║
╠═════════╬══════╬═══════════╬═══════════════╣
║       1 ║ S    ║ Secondary ║ 2             ║
║       1 ║ V    ║ Vertical  ║ NULL          ║
║       2 ║ U    ║ Uniform   ║ 1             ║
║       3 ║ I    ║ Industry  ║ 2             ║
║       3 ║ F    ║ First     ║ NULL          ║
╚═════════╩══════╩═══════════╩═══════════════╝

---

SQL数据本质上是未排序的…是否有任何内容（除了显示的“顺序”之外）也就是说，哪条记录是第一条/第二条/第三条？你能将这种格式保留在前端，而不是试图通过sql强制执行吗？@第十二条只要计数是，顺序就无关紧要。sql数据中的任何一条都是天生未排序的……是否有任何内容（除了显示的“顺序”之外）也就是说，哪条记录是第一条/第二条/第三条？你能将这种格式保留在前端，而不是通过sql强制执行吗？只要计数是行中的任何一条，顺序就不重要了