必须为K_RT_MasterRetailStores的每个联接使用不同的别名。

其他人说要用不同的别名，但也许你不清楚他们的意思：

select convert(varchar,FT.date,103)as date, MR_from.branch as frombranch,
        PD.productname as product,FT.vehicleno,FT.dcno,FT.tobranch 
from K_RT_FixedAssetTransfer FT
inner join K_RT_MasterRetailStores MR_from --<-- First alias
           on MR_from.sno = FT.frombranch 
inner join K_RT_ProductDetails PD on PD.sno=FT.product
inner join K_RT_MasterRetailStores MR_to --<-- Second alias
           on MR_to.sno = FT.tobranch 
where FT.date between @fromdate and  @todate

我注意到您没有使用SELECT列表中第二个连接的任何内容，也许您想使用它来代替FT.tobranch？

select convert(varchar,FT.date,103)as date, MR_from.branch as frombranch,
        PD.productname as product,FT.vehicleno,FT.dcno,MR_to.branch 
from K_RT_FixedAssetTransfer FT
inner join K_RT_MasterRetailStores MR_from on MR_from.sno = FT.frombranch 
inner join K_RT_ProductDetails PD on PD.sno=FT.product
inner join K_RT_MasterRetailStores MR_to on MR_to.sno = FT.tobranch 
where FT.date between @fromdate and  @todate

您已使用同一别名在上两次加入K_RT_MasterRetailStores。
根据此连接是否需要插入两次，您需要

• 删除第二个连接
• 使用其他别名

--Rename the alias names

inner join K_RT_MasterRetailStores MR1 on MR1.sno = FT.frombranch

inner join K_RT_MasterRetailStores MR2 on MR2.sno = FT.tobranch