How to execute a Begin-End Transact SQL statements in Apache nifi?

Question

I am trying to execute an SQL statement with Begin - End and Cursor in between using Execute SQL processor in Apache Nifi. But this is throwing an error telling "Unable to execute SQL select query". How can I execute transact SQL statements in nifi? Which processor is best suited for this?

Below is the SQL code snippet that I am trying to execute,

DECLARE @Cursor CURSOR
DECLARE @stlsn binary(10), @endlsn binary(10), @sequal binary(10), @op char, @upm varbinary(128), @rn numeric, @tg char(10), @ti char(10), @ln char(10), @dv char(10), @cid int

BEGIN
    SET @Cursor = CURSOR FOR
    SELECT * FROM cdc.dbo_SampleDB_CT  

    OPEN @Cursor 
    FETCH NEXT FROM @Cursor INTO @stlsn, @endlsn, @sequal, @op, @upm, @rn, @tg, @ti, @ln, @dv, @cid

    WHILE @@FETCH_STATUS = 0
    BEGIN
        SELECT @op, @rn, @tg, @ti, @ln, @dv
        IF @op= 1 Execute ('DELETE FROM dbo.NewDB WHERE RNo = '+@rn)
        IF @op= 2 Execute ('INSERT INTO dbo.NewDB VALUES ('+@rn+','''+@tg+''','''+@ti+''','''+@ln+''','''+@dv+''')')

      FETCH NEXT FROM @Cursor INTO @stlsn, @endlsn, @sequal, @op, @upm, @rn, @tg, @ti, @ln, @dv, @cid
    END;

    CLOSE @Cursor ;
    DEALLOCATE @Cursor;
END;

Answer 1

This doesn't need to be dynamic at all. You can just do a joined DELETE and an INSERT...SELECT... .

You haven't specified your column names so I'm guessing a bit here.

DELETE FROM n
FROM dbo.NewDB n
JOIN cdc.dbo_SampleDB_CT c ON c.RNo = n.RNo
WHERE c.__$operation = 1;

INSERT INTO dbo.NewDB
SELECT c.RNo,c.tg,c.ti,c.ln,c.dv
FROM cdc.dbo_SampleDB_CT c
WHERE  c.__$operation = 2;

I note that you haven't dealt with CDC update rows.