Run large compare in Batches - sql

Question

I need to compare large tables with millions of rows and insert the differences into a log table.
The problem is that stored proc grows (LDF), and the database disk space is limited.
I know that commit will write the LDF to the MDF.
How can I perform the following compare in batches, and commit every hundred thousand rows?
BEGIN TRY
BEGIN TRANSACTION;
INSERT INTO dbo.CustomerLog
( OnlineStore ,
PhoneNumber ,
ChangeType
)
SELECT 'Online Store a' ,
AreaCode + PhoneNumber ,
'Added'
FROM dbo.StoreAList a
WHERE NOT EXISTS ( SELECT 1
FROM dbo.StoreAListCompare b
WHERE ( b.AreaCode + b.PhoneNumber ) = ( a.AreaCode
+ a.PhoneNumber ) );
COMMIT TRANSACTION
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
END CATCH;
CREATE TABLE [dbo].[StoreAList](
[ListID] [bigint] IDENTITY(1,1) NOT NULL,
[AreaCode] [char](3) NOT NULL,
[PhoneNumber] [char](7) NOT NULL,
[RecordDate] [datetime] NULL CONSTRAINT [DF_StoreAList_RecordDate] DEFAULT (getdate())
) ON [PRIMARY]
CREATE TABLE [dnc].[StoreAListCompare](
[ListID] [BIGINT] IDENTITY(1,1) NOT NULL,
[AreaCode] [CHAR](3) NOT NULL,
[PhoneNumber] [CHAR](7) NOT NULL,
[RecordDate] [DATETIME] NULL DEFAULT (GETDATE())
) ON [PRIMARY]

Answer 1

You can use the ##rowcount system variable and do the insert in batches until ##rowcount hits 0.
Note the added AND NOT EXISTS in dbo.CustomerLog...
Ex:
DECLARE #BATCHSIZE INT=100000
WHILE #BATCHSIZE>0
BEGIN
BEGIN TRY
BEGIN TRANSACTION;
INSERT INTO dbo.CustomerLog
( OnlineStore ,
PhoneNumber ,
ChangeType
)
SELECT TOP(#BATCHSIZE)
'Online Store a' ,
AreaCode + PhoneNumber ,
'Added'
FROM dbo.StoreAList a
WHERE NOT EXISTS ( SELECT 1
FROM dbo.StoreAListCompare b
WHERE ( b.AreaCode + b.PhoneNumber ) = ( a.AreaCode + a.PhoneNumber ) )
AND NOT EXISTS (SELECT 1
FROM dbo.CustomerLog CL
WHERE 'Online Store a'=CL.OnlineStore
AND AreaCode + PhoneNumber=CL.PhoneNumber
AND 'Added'=CL.ChangeType);
SET #BATCHSIZE=##ROWCOUNT
COMMIT TRANSACTION
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
SET #BATCHSIZE=0
END CATCH;
END