[英]Using a while loop with SQL cursors?
我正在创建一个sql脚本,我有2个游标可通过表游标和公司游标遍历数据。 我在使用while循环将公司光标放在一起以将数据复制到架构时遇到问题,我需要使用If语句回答以下问题
该表是否包含companyID列? if语句检查公司ID(如果是),然后根据游标中的companyID复制数据
我有一个@firstLoop声明
这是我的光标特定的代码
DECLARE @firstLoop BIT
SET @firstLoop = true
----------- Cursor specific code starts here ------------
-- company cursor
declare copyCompanyDataCursor CURSOR fast_forward FOR
SELECT ID from #CompanyIDs;
open copyCompanyDataCursor
fetch next from copyCompanyDataCursor into @Company_Id;
WHILE @@FETCH_STATUS = 0
BEGIN
declare @processorder int;
declare @tablename varchar(500);
-- table cursor
declare copyTableDataCursor CURSOR fast_forward FOR
SELECT processorder,tablename from #TableList4 order by processorder;
open copyTableDataCursor
fetch next from copyTableDataCursor into @processorder, @tablename;
while @@FETCH_STATUS = 0
BEGIN
SET IDENTITY_INSERT [c365online_script1.dbo.tCompany] OFF
-- Does the table have a companyID column? if statement checking for company id
-- if yes then copy data based on companyID in cursor
-- if no check if this is the first time through company loop and copy all data
-- if @firstloop company exists look at information schema
-- insert into c365online_script1.dbo.tCompany(selec
EXEC('INSERT ' + @Destination_Database_Name + '.dbo.' + @tablename + ' SELECT * FROM ' + @Source_Database_Name + '.dbo.' + @tablename + ')')
-- company logic
SET IDENTITY_INSERT [c365online_script1.dbo.tCompany] ON
FETCH NEXT FROM copyTableDataCursor into @processorder,@tablename;
END
close copyTableDataCursor;
Deallocate copyTableDataCursor;
--INSERT INTO c365online_script1.dbo.tCompany
--SELECT *
--FROM production2.tCompany
--WHERE ISNULL(CompanyID, 0) = 0 -- copy all data where id is equal to zero
--@Destination_Database_Name
--
--EXEC(INSERT + @Destination_Database_Name + '.dbo.' + @tablename + ' SELECT * FROM ' + @Source_Database_Name + '.dbo.' + @tablename + ' WHERE ' + @Source_Database_Name + '.dbo.' + @tablename + '.CompanyID = ' + @Company_Id + ')'
SET @firstLoop = false;
FETCH NEXT FROM copyCompanyDataCursor into @Company_Id;
END
CLOSE copyCompanyDataCursor;
DEALLOCATE copyCompanyDataCursor;
我建议您将两个CURSORS都替换为while循环。
SQL Server中的CURSORS成本性能非常差,而用While循环替换为临时表肯定会提高性能,并且您必须编写更轻松的编码类型。
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