Big Data paging algorithm

Create procedure getpage

@ Tblname varchar (255), -- table name
@ Strgetfields varchar (1000) = '*', -- the column to be returned
@ Fldname varchar (255) = '', -- Name of the sorted Field
@ Pagesize Int = 10, -- page size (number of records per page)
@ Pageindex Int = 1, -- page number
@ Docount bit = 0, -- returns the total number of records. If the value is not 0, the number of records is returned.
@ Ordertype bit = 0, -- set the sorting type. If the value is not 0, the sorting type is descending.
@ Strwhere varchar (1500) = ''-- Query condition (Note: Do not add where)
As
Declare @ strsql varchar (5000) -- subject sentence
Declare @ strtmp varchar (110) -- Temporary Variable
Declare @ strorder varchar (400) -- sort type
If @ docount! = 0
Begin
If @ strwhere! =''
Set @ strsql = "select count (*) as total from [" + @ tblname + "] Where" + @ strwhere
Else
Set @ strsql = "select count (*) as total from [" + @ tblname + "]"
End -- above Code It means that if @ docount is not passed over 0, the total number of statistics will be executed. All the code below is 0 @ docount
Else
Begin
If @ ordertype! = 0 // descending order (DESC)
Begin
Set @ strtmp = "<(select Min"
Set @ strorder = "order by [" + @ fldname + "] DESC"
-- If @ ordertype is not 0, execute the descending order. This sentence is very important!
End
Else // ascending (ASC)
Begin
Set @ strtmp = "> (select Max"
Set @ strorder = "order by [" + @ fldname + "] ASC"
End
If @ pageindex = 1 // page number
Begin
If @ strwhere! =''
Set @ strsql = "select top" + STR (@ pagesize) + "" + @ strgetfields + "from [" + @ tblname + "] Where" + @ strwhere + "" + @ strorder
Else
Set @ strsql = "select top" + STR (@ pagesize) + "" + @ strgetfields + "from [" + @ tblname + "]" + @ strorder
-- Execute the above Code on the first page, which will speed up the execution.
End
Else
Begin -- The following Code grants @ strsql the SQL code to be actually executed
Set @ strsql = "select top" + STR (@ pagesize) + "" + @ strgetfields + "from [" + @ tblname + "] Where [" + @ fldname + "]" + @ strtmp + "([" + @ fldname +" ]) from (select top "+ STR (@ PageIndex-1) * @ pagesize) + "[" + @ fldname + "] from [" + @ tblname + "]" + @ strorder + ") as tbltmp)" + @ strorder
If @ strwhere! =''
Set @ strsql = "select top" + STR (@ pagesize) + "" + @ strgetfields + "from [" + @ tblname + "] Where [" + @ fldname + "]" + @ strtmp + "([" + @ fldname +" ]) from (select top "+ STR (@ PageIndex-1) * @ pagesize) + "[" + @ fldname + "] from [" + @ tblname + "] Where" + @ strwhere + "" + @ strorder + ") as tbltmp) and "+ @ strwhere +" "+ @ strorder
End
End
Exec (@ strsql)
Go