sql - An expression of non-boolean type specified in a context where a condition is expected, near '@orderwhere'

Question

Why is the following syntax generates the error "An expression of non-boolean type specified in a context where a condition is expected, near '@orderwhere'"

use orders
declare @orderwhere varchar(5000)
set @orderwhere = 'order_status.step = 1'
select order_status.order_id
from order_status
where @orderwhere

Answer 1

您不能让查询的某些部分是动态的。它必须是全部或全部。然后使用EXEC()运行您的动态查询

exec('select order_status.order_id
      from order_status
      where ' + @orderwhere)

Answer 2

您的 where 子句是一个字符串。您应该使用动态 SQL 或类似的东西：

use orders
declare @orderwhere varchar(5000)
set @orderwhere = '1'
select order_status.order_id
from order_status
where order_status.step = @orderwhere