Compare tables on Linked Servers SQL dynamically - sql-server

Question

I have to compare table (SIB$) to get unmatched records on two different LINKED SERVERS (LATESTDUMP, OLDDUMP) that are identical. I have already tried to create a dynamic query. Can some one please help me with following:
1) Is there a way where I dont have to pass the column names to the code and the code dynamically gets the column names and use it as the column list to compare.
So all I have to do is pass to the stored proc the two table names
Code i have worked on:
DECLARE #sql nvarchar(max) = ' ((SELECT * FROM LATESTDUMP...SIB$) t1 FULL
OUTER JOIN (SELECT * FROM OLDDUMP...SIB$) t2
ON t1.id = t2.id
WHERE
t1.id IS NULL OR
t2.id IS NULL)'
SELECT #sql += ' or t1.' + quotename(column_name) + ' <> t2.' +
quotename(column_name) from information_schema.columns where table_name =
'SIB$'

Answer 1

Looks like you might want to look at the MERGE statement that's been available since SQL 2008.
https://learn.microsoft.com/en-us/sql/t-sql/statements/merge-transact-sql

Answer 2

Here's some code to get you started. It pulls out a primary key (assumes one column primary keys, which may or may not be a valid assumption for you), and grabs a comma-delimited string list of the remaining columns.
From here you can use split-string to build a sql string that joins the two same-named tables from the hard-coded linked servers on the primary key, comparing each of the columns for difference, and then execute the dynamic SQL. I've included some test scaffolding so you can work it through:
DECLARE #tableName sysname;
SET #tableName = 'some table'
-- Validate parameter
IF #tableName IS NULL OR NOT EXISTS (SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = #tableName AND TABLE_TYPE = 'BASE TABLE')
BEGIN
RAISERROR ('Invalid table name specified', 16, 1);
RETURN;
END;
-- Validate table has a primary key
IF NOT EXISTS (SELECT 1 FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE CONSTRAINT_TYPE = 'PRIMARY KEY' AND TABLE_NAME = #tableName)
BEGIN
RAISERROR ('Specified table does not have a primary key', 16, 1);
RETURN;
END;
-- Get info about the Primary Key columns
DECLARE #pkcolName sysname;
SELECT #pkcolName = c.COLUMN_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu ON tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.COLUMNS c ON kcu.TABLE_NAME = c.TABLE_NAME AND kcu.COLUMN_NAME = c.COLUMN_NAME
WHERE tc.CONSTRAINT_TYPE = 'PRIMARY KEY' AND tc.TABLE_NAME = #tableName AND kcu.ORDINAL_POSITION = 1
-- Grab the names of all the remaining columns
DECLARE #nonKeyColumns nvarchar(MAX);
SELECT #nonKeyColumns = STUFF ( ( SELECT N'], [' + c.name
FROM sys.columns c
WHERE object_id = (select top 1 object_id FROM sys.objects where name = #tableName)
AND c.name <> #pkcolName
ORDER BY c.column_id
FOR XML PATH('')), 1, 2, '') + ']';
SELECT #pkcolName
SELECT #nonKeyColumns