Table sync and copy into other table - sql

Question

I have two tables. Table A and Table B. They are identical. Ever 10 min i need to check if there any changs happend (New and updated) to Table A and copy into Table B. And also enter in Table C if i see a differance and new.
I also need to log if there any new records in Table A to table B and Table C
Iam planning to do join and compare the records. If i do that i might miss the new records. Is there any better way to do this kind of sync. It has to be done in SQL i can not use any other tools like SSIS.

Answer 1

Here's what I came up with in making some simple tables in SQL:
# create some sample tables and data
DROP TABLE alpha;
DROP TABLE beta;
DROP TABLE charlie;
CREATE TABLE `alpha` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`data` VARCHAR(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MYISAM DEFAULT CHARSET=latin1;
CREATE TABLE `beta` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`data` VARCHAR(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MYISAM DEFAULT CHARSET=latin1;
CREATE TABLE `charlie` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`data` VARCHAR(32) DEFAULT NULL,
`type` VARCHAR(16) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MYISAM DEFAULT CHARSET=latin1;
INSERT INTO alpha (data) VALUES ("a"), ("b"), ("c"), ("d"), ("e");
INSERT INTO beta (data) VALUES ("a"), ("b"), ("c");
# note new records of A, log in C
INSERT INTO charlie (data, type)
(SELECT data, "NEW"
FROM alpha
WHERE id NOT IN
(SELECT id
FROM beta));
# insert new records of A into B
INSERT INTO beta (data)
(SELECT data
FROM alpha
WHERE id NOT IN
(SELECT id
FROM beta));
# make a change in alpha only
UPDATE alpha
SET data = "x"
WHERE data = "c";
# note changed records of A, log in C
INSERT INTO charlie (data, type)
(SELECT alpha.data, "CHANGE"
FROM alpha, beta
WHERE alpha.data != beta.data
AND alpha.id = beta.id);
# update changed records of A in B
UPDATE beta, alpha
SET beta.data = alpha.data
WHERE alpha.data != beta.data
AND alpha.id = beta.id;
You would of course have to expand this for the type of data, number of fields, etc. but this is a basic concept if it helps.

Answer 2

It's a pity that you can't use SSIS (not allowed?) because it's built for this kind of thing. Anyway, using pure SQL you should be able to something like the following: if your tables have got a created/updated timestamp column, then you could query Table B for the highest one and get all records from table A with timestamps higher than that one.
If there's no timestamp to use, hopefully there's a PK like an int that can be used in the same way.
Hope that helps?
Valentino.

Answer 3

I would try using a trigger or transactional replication.

Answer 4

Hopefully you have a good unique key that is used in the tables. To get new records you can do the following:
SELECT * FROM tableA
WHERE NOT EXISTS( SELECT * FROM tableB WHERE pkey.tableA = pkey.TableB)