MySql与SqlServer的一些常用用法的差别

IF Boolean_expression 
     { sql_statement | statement_block } 
[ ELSE 
     { sql_statement | statement_block } ] 
 
-- 若要定义语句块，请使用控制流关键字 BEGIN 和 END。

IF search_condition THEN statement_list
    [ELSEIF search_condition THEN statement_list] ...
    [ELSE statement_list]
END IF

declare @tempShoppingCart table (ProductId int, Quantity int)
insert into @tempShoppingCart (ProductId, Quantity)
	select ProductId, Quantity from ShoppingCart where UserGuid = @UserGuid


declare @productId int
declare @quantity int
declare tempCartCursor cursor for 
		select ProductId, Quantity from @tempShoppingCart

open tempCartCursor
fetch next from tempCartCursor into @productId, @quantity
while  @@FETCH_STATUS = 0
begin
	update Product set SellCount = SellCount + @quantity	where productId = @productId

	fetch next from tempCartCursor into @productId, @quantity
end

close tempCartCursor
deallocate tempCartCursor

declare m_done int default 0;
declare m_sectionId int;
declare m_newsId int;

declare _cursor_SN cursor for select sectionid, newsid from _temp_SN;
declare continue handler for not found set m_done = 1;

create temporary table _temp_SN 
	select sectionid, newsid from SectionNews  group by sectionid, newsid having count(*) > 1;

open _cursor_SN;
while( m_done = 0 ) do
	fetch _cursor_SN into m_sectionId, m_newsId;
	
	if( m_done = 0 ) then 
		-- 具体的处理逻辑
	end if;
end while;
close _cursor_SN;
drop table _temp_SN;

create procedure GetProductByCategoryId( 
    @CategoryID int, 
    @PageIndex int = 0, 
    @PageSize int = 20, 
    @TotalRecords int output
) 
as
begin
     
declare @ResultTable table
( 
    RowIndex int, 
    ProductID int, 
    ProductName nvarchar(50), 
    CategoryID int, 
    Unit nvarchar(10), 
    UnitPrice money, 
    Quantity int
); 
     
insert into @ResultTable 
select row_number() over (order by ProductID asc) as RowIndex, 
       p.ProductID, p.ProductName, p.CategoryID, p.Unit, p.UnitPrice, p.Quantity 
from   Products as p 
where CategoryID = @CategoryID; 
       
select  @TotalRecords = count(*) from  @ResultTable; 
     
select * 
from   @ResultTable 
where  RowIndex > (@PageSize * @PageIndex) and RowIndex <= (@PageSize * (@PageIndex+1)); 
     
end;

当然，SqlServer中并不只有这一种写法，只是这种写法是比较常见而已。

create procedure GetProductsByCategoryId(
   in _categoryId int,
   in _pageIndex int,
   in _pageSize int,
   out _totalRecCount int
)
begin
 
   set @categoryId = _categoryId;
   set @startRow = _pageIndex * _pageSize;
   set @pageSize = _pageSize;
 
   prepare PageSql from 
	‘select sql_calc_found_rows * from product  where categoryId = ? order by ProductId desc limit ?, ?‘;
   execute PageSql using @categoryId, @startRow, @pageSize;
   deallocate prepare PageSql;
   set _totalRecCount = found_rows();
 
end