c# - 使用 C# 在 MYSQL 中声明局部变量时发生 fatal error

Question

我在 MYSQL 中声明局部变量时遇到异常。请建议我如何解决这个问题..

异常:
命令执行期间遇到 fatal error 。
内部异常:
{“必须定义参数'@OrderofParent'。”}

代码片段:

   StringBuilder sbQuery = new StringBuilder(); <br>
    sbQuery.Append(@"Declare @OrderofParent INT; SET @OrderofParent = 0;
                    select top 1 @OrderofParent = OrderofParent from Filter group        by          OrderofParent order by OrderofParent desc;

    select 'FamilyType' as Mode, 0 as Id, 'Complexity Type' as FilterName, null as FilterCreatedDate, 0 as IsDisabled,0 as ParentId,                                               @OrderofParent as OrderofParent,1 as TagDisplay, 0 as ParentCount from I_FamilyTypePrice
union
Select 'Filter', Id, FilterName, FilterCreatedDate, IsDisabled, f.ParentId, OrderofParent, TagDisplay, 0 from Filter f where f.ParentID = 0 
union
select 'FamilyType', ft.Id, FamilyTypeName, CreatedDate, 0,0, @OrderofParent,0, count(complexityType) from I_FamilyTypePrice ft join Family f on f.complexityType = ft.Id where version = @version and IsActive = 1 and Uploaded = 1; ");

Answer 1

添加“允许用户变量=True”在连接字符串参数中