Question

我正在使用Sql Server。在存储过程中，我需要根据传递的参数构建一个sql select。基于我需要为WHERE子句添加条件的参数。我需要这个sql来声明一个游标。

我需要的是像

DECLARE mycursor CURSOR LOCAL FOR
SELECT username FROM mytable Where <condition1>
IF(parameter 1 is not empty)
AND <conditions>
IF(parameter 2 is not empty)
AND <condition3>

在t-sql中执行此操作的最佳方法是什么？

Answer 1

如果您只想根据某些参数是否设置过滤某些条件，只需在WHERE子句中包含参数，如下所示：

SELECT username FROM mytable 
WHERE <StaticCondition>
    AND (@Parameter1 IS NULL OR <Parameter1Condition>)
    AND (@Parameter2 IS NULL OR <Parameter2Condition>)
    AND ...

无论是直接使用输出，还是需要select语句来声明游标，都可以使用此方法。

Answer 2

我知道发布一个链接通常不赞成，但这可能是我在搜索SQL＆＃39;上发现的最好的文章。选项＆amp;非常详细。

http://www.sommarskog.se/dyn-search-2008.html

整体查询，例如

http://www.sommarskog.se/dynsearch-2008/search_orders_4a.sp

**      SELECT o.OrderID, o.OrderDate, od.UnitPrice, od.Quantity,
         c.CustomerID, c.CompanyName, c.Address, c.City, c.Region,
         c.PostalCode, c.Country, c.Phone, p.ProductID,
         p.ProductName, p.UnitsInStock, p.UnitsOnOrder
  FROM   Orders o
  JOIN   [Order Details] od ON o.OrderID = od.OrderID
  JOIN   Customers c ON o.CustomerID = c.CustomerID
  JOIN   Products p ON p.ProductID = od.ProductID
  WHERE  (o.OrderDate >= @fromdate OR @fromdate IS NULL)
    AND  (o.OrderDate <= @todate OR @todate IS NULL)
    AND  (od.UnitPrice >= @minprice OR @minprice IS NULL)
    AND  (od.UnitPrice <= @maxprice OR @maxprice IS NULL)
    AND  (o.CustomerID = @custid OR @custid IS NULL)
    AND  (c.CompanyName LIKE @custname + '%' OR @custname IS NULL)
    AND  (c.City = @city OR @city IS NULL)
    AND  (c.Region = @region OR @region IS NULL)
    AND  (c.Country = @country OR @country IS NULL)
    AND  (od.ProductID = @prodid OR @prodid IS NULL)
    AND  (p.ProductName LIKE @prodname + '%' OR @prodname IS NULL)**

T SQL - 构建Select语句

2 个答案: