T-SQL by Example
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INNER JOIN

Join two tables with matching keys; basic patterns.

What you’ll learn

  • Join two tables on a key; select columns from both sides.
SELECT o.OrderID, o.OrderDate, c.CustomerID, c.Name
FROM dbo.Orders AS o
JOIN dbo.Customers AS c
  ON c.CustomerID = o.CustomerID;

Notes

  • Join predicates belong in ON, not WHERE (esp. with OUTER joins).
  • Add selective predicates to help the optimizer choose a seek.