SELECT
Retrieve columns from tables.
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SQL Essentials
Query language terms for analysts and developers.
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Flashcards
FROM
Specify the source table(s).
WHERE
Filter rows by a condition.
JOIN
Combine rows from related tables.
INNER JOIN
Return matching rows from both tables.
LEFT JOIN
Keep all left rows; match right when possible.
GROUP BY
Aggregate rows by column values.
ORDER BY
Sort result rows.
PRIMARY KEY
Unique identifier for a table row.
FOREIGN KEY
Column referencing another table's key.
INDEX
Structure that speeds up lookups.
NULL
Missing or unknown value.
TRANSACTION
Atomic unit of work (commit/rollback).
NORMALIZE
Organize data to reduce redundancy.