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644. JOIN USING Multiple Columns

Use USING with multiple shared columns to define a composite JOIN relationship.

📘 Lesson 644 of 728 ⏱ 14 min 🎯 Advanced

USING can specify multiple columns when a relationship depends on a combination of same-named columns.

Some business keys are composite and require more than one column to uniquely identify a matching record.

Match records using both BranchID and AccountType.

SQL 
SELECT
    BranchID,
    AccountType,
    AccountNumber
FROM Accounts
INNER JOIN AccountBalances
USING (BranchID, AccountType);

Used in financial systems, regional data, composite business keys, and multi-column relationships.

  • Multiple columns can form a composite relationship.
  • All specified USING columns participate in the match.
  • Column names must match.
  • Composite keys require careful validation.
  • A partial key can create incorrect matches.
Can USING contain multiple columns?

Yes. Multiple same-named columns can be specified to form a composite JOIN condition.

Why use multiple JOIN columns?

Some relationships require a combination of columns to uniquely identify the matching record.

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