我想写一个 sql 查询来获取数据:
1. when param = 'all' it should list data across the table
2. when param = 'yes' it should list data where invoicenumber is not empty.
3. when param = 'no' it should list data where invoicenumber is empty.
我在下面的查询中尝试了是和否
declare @invoiced as nvarchar(10) = 'no'
select * from OrderSummary
where
((@invoiced = 'yes') or (InvoiceNumber = ''))
and
((@invoiced = 'no') or (InvoiceNumber <> ''))
现在我也想合并所有条件,任何人都可以建议我如何实现这一点