
Here is a practical path you can follow. Try this approach and This is the example to start
-- List tables
SELECT s.name AS schema_name, t.name AS table_name
FROM sys.tables t JOIN sys.schemas s ON s.schema_id = t.schema_id
ORDER BY s.name, t.name;
-- Columns for a table
EXEC sys.sp_help 'dbo.Orders';
-- Foreign keys in the database
SELECT fk.name, OBJECT_NAME(fk.parent_object_id) AS child_table,
cpa.name AS child_col, OBJECT_NAME(fk.referenced_object_id) AS parent_table,
cref.name AS parent_col
FROM sys.foreign_keys fk
JOIN sys.foreign_key_columns fkc ON fkc.constraint_object_id = fk.object_id
JOIN sys.columns cpa ON cpa.object_id = fkc.parent_object_id AND cpa.column_id = fkc.parent_column_id
JOIN sys.columns cref ON cref.object_id = fkc.referenced_object_id AND cref.column_id = fkc.referenced_column_id
ORDER BY child_table, fk.name;
SELECT o.OrderID, o.OrderDate, c.CustomerName
FROM dbo.Orders o
JOIN dbo.Customers c
ON c.CustomerID = o.CustomerID
WHERE o.OrderDate >= '2025-01-01';
SELECT c.CustomerID, c.CustomerName, o.OrderID
FROM dbo.Customers c
LEFT JOIN dbo.Orders o
ON o.CustomerID = c.CustomerID;
SELECT p.ProductID, p.ProductName, c.CategoryName
FROM dbo.Products p
JOIN dbo.ProductCategory pc
ON pc.ProductID = p.ProductID
JOIN dbo.Categories c
ON c.CategoryID = pc.CategoryID;
SELECT f.FactID, d.CalendarDate, d.FiscalYear
FROM dbo.FactSales f
JOIN dbo.DimDate d
ON d.CalendarDate = f.CalendarDate
AND d.FiscalYear = f.FiscalYear;
SELECT *
FROM SalesDB.dbo.Orders o
JOIN MasterData.dbo.Customers c ON c.CustomerID = o.CustomerID;
SELECT *
FROM [LOCALSERVER].SalesDB.dbo.Orders o
JOIN [LINKEDSRV].MasterData.dbo.Customers c ON c.CustomerID = o.CustomerID;
-- Quick cardinality check
SELECT COUNT(*) FROM dbo.Orders; -- base
SELECT COUNT(*) FROM dbo.Orders o
JOIN dbo.Customers c ON c.CustomerID = o.CustomerID; -- after join