Assistance with IF Statement - sql

Question

I need some assistance with my tsql , I have knowledge of sql but mainly just querying tables and im finding tsql and loops quite difficult to finish off.
I have hit a sticking point with my IF STATEMENT.
As you can see I have wrote the loop and attempted some debugging and the code is correct so far.
In the Else section
I need to check if it’s the first time through the loop using #firstloop and then copy all data , its mainly the loop that I’m having problems with and could do with help on getting a starting point.
I am using cursors but have been told it won’t affect performance because it’s not doing too much work and I would appreciate any help with the problem.I have also been told that some sections are Hard coded such as Production2 which should be #Source_Database_Name.
declare #Source_Database_Name varchar(255) = 'Production2';
declare #Destination_Database_Name varchar(255) = 'c365online_script1';
declare #Company_Id int = 1 --declare a companyid
CREATE TABLE #CompanyID (ID bigint)
INSERT INTO #CompanyID(ID)
VALUES('15')
--FIRST CURSOR LOOP THROUGH THIS TABLE
CREATE TABLE #TableList (
processorder int,
tablename NVARCHAR(100)
)
INSERT INTO #TableList (processorder, tablename )
VALUES
(1, 'tProperty');
DECLARE #firstLoop BIT
--SET #firstLoop = true
DECLARE #Counter INT -- counting variable
----------- Cursor specific code starts here ------------
-- company cursor
declare copyCompanyDataCursor CURSOR fast_forward FOR
SELECT ID from #CompanyID;
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 #TableList order by processorder;
open copyTableDataCursor
fetch next from copyTableDataCursor into #processorder, #tablename;
while ##FETCH_STATUS = 0
BEGIN
SET IDENTITY_INSERT [c365online_script1].[dbo].[tCompany] ON
-- Does the table have a companyID column? if statement checking for company id
IF EXISTS(SELECT * FROM Production2.INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME='CompanyID' and TABLE_NAME=#tablename)
BEGIN
declare #debug varchar(max)
SET #debug = 'INSERT INTO ' + #Destination_Database_Name + '.dbo.' + #tablename + ' SELECT * FROM ' + #Source_Database_Name + '.dbo.' + #tablename + ' WHERE ' + #Source_Database_Name + '.dbo.' + #tablename + '.CompanyID = ' + CAST(#Company_Id as varchar(10))
print #debug
--EXEC(#debug)
--EXEC('INSERT INTO ' + #Destination_Database_Name + '.dbo.' + #tablename + ' SELECT * FROM ' + #Source_Database_Name + '.dbo.' + #tablename + ' WHERE ' + #Source_Database_Name + '.dbo.' + #tablename + '.CompanyID = ' + #Company_Id )
END
ELSE
-- if no check if this is the first time through company loop and copy all data- if #firstloop company exists look at information schema
BEGIN
Print 'No'
END
-- if yes then copy data based on companyID in cursor
--EXEC('INSERT INTO ' + #Destination_Database_Name + '.dbo.' + #tablename + ' SELECT * FROM ' + #Source_Database_Name + '.dbo.' + #tablename )
-- company logic
SET IDENTITY_INSERT [c365online_script1].[dbo].[tCompany] OFF
FETCH NEXT FROM copyTableDataCursor into #processorder,#tablename;
END
close copyTableDataCursor;
Deallocate copyTableDataCursor;

Answer 1

Not sure why you are using the cursor. To answer your question of "checking if its the first time gone through loop" then below is the soullution for this.
Declare a variable above "while ##FETCH_STATUS = 0" Line.
somethign like "Firsttime = 0 "
Under IF , "Firsttime = 1 " Which means this is not first time.
In ELSE , check
---> if "Firsttime = 0 " Then it mean first time
---> if "Firsttime = 1 " Then it mean its not first time