Question

我需要创建一个带有order by - 子句的视图，其中包含续集，tinytds和MSSQL

当我这样做时，我收到错误

TinyTds::Error: The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions, unless TOP or FOR XML is also specified. (Sequel::DatabaseError)

我的示例代码：

require 'sequel'

DB = Sequel.tinytds(
                    :host     =>  'server', 
                    :database=> 'DB',
                )     
#Remove data from previous test
DB.drop_table(:testtab1) if DB.table_exists?(:testtab1)
DB.drop_view(:v_testtab1) rescue Sequel::DatabaseError
DB.drop_view(:v_testtab2) rescue Sequel::DatabaseError

DB.create_table(:testtab1){
  primary_key :id
  field :a, :type => :nvarchar, :size => 10
  field :b, :type => :nvarchar, :size => 10
}

#Here the error comes up
#"SELECT * FROM `testtab1` ORDER BY `b`"
DB.create_view(:v_testtab1, DB[:testtab1].order_by(:b))

查看solution on SQL-side很简单。而不是

SELECT * FROM `testtab1` ORDER BY `b`

我需要一个

SELECT top 100 percent * FROM `testtab1` ORDER BY `b`

我找到了一个带有额外过时列的解决方案（没有列dummy我得到一个无效的逗号）：

sel = DB[:testtab1].select(Sequel.lit('top 100 percent "" as dummy'), *DB[:testtab1].columns)
#SELECT top 100 percent "" as dummy, [ID], [A], [B] FROM [TESTTAB1]
DB.create_view(:v_testtab2, sel.order_by(:b))

可以使用limit：

制作类似的解决方案

#Take a big number to get all entries.
#DB[:testtab1].count would take the number in moment of view creation, not usage.
sel = DB[:testtab1].limit(99999999999) 
#SELECT TOP (99999999999) * FROM [TESTTAB1]
DB.create_view(:v_testtab3, sel.order_by(:b))

但我正在寻找更好的解决方案。还有其他更好的可能性吗？

如果重要：

Ruby 2.1
续集4.19
tiny_tds-0.6.2-x64的的mingw32
MSSQL 10.50.2500.0,64位

续集：如何在tinytds的视图中使用'order by'

0 个答案: