本文介绍了公用表表达式，为什么要分号?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
通常在SQL Server Common Table Expression 子句中，语句前有分号，像这样:
Usually in SQL Server Common Table Expression clause there is semicolon in front of the statement, like this:
;WITH OrderedOrders AS --semicolon here
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS 'RowNumber'
FROM Sales.SalesOrderHeader
)
SELECT *
FROM OrderedOrders
WHERE RowNumber BETWEEN 50 AND 60
为什么?
推荐答案
- 为了避免歧义，因为 WITH 可以在别处使用
..FROM..WITH (NOLOCK)..
RESTORE..WITH MOVE.. - 在 SQL Server 中使用
;终止语句是可选的 - To avoid ambiguity because WITH can be used elsewhere
..FROM..WITH (NOLOCK)..
RESTORE..WITH MOVE.. - It's optional to terminate statements with
;in SQL Server
总而言之，前面的语句必须在 WITH/CTE 之前终止.为了避免错误，大多数人使用 ;WITH 因为我们不知道 CTE 之前是什么
Put together, the previous statement must be terminated before a WITH/CTE. To avoid errors, most folk use ;WITH because we don't know what is before the CTE
所以
DECLARE @foo int;
WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
...;
与
DECLARE @foo int
;WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
...;
MERGE 命令有类似的要求.
The MERGE command has a similar requirement.
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