Subqueries Development Tutorials, Guides & Insights

When joining multiple tables, start with the table that filters out the most rows.

Ensure that the columns used in joins have indexes. This can significantly reduce the time taken to execute join operations.

• ROW_NUMBER(): Assigns unique sequential numbers.
• RANK(): Assigns ranks with gaps on ties.
• DENSE_RANK(): Ranks without gaps.
• NTILE(n): Divides rows into n groups.
• LEAD() / LAG(): Accesses next/previous rows.

SELECT column1, window_function() OVER (PARTITION BY column ORDER BY column)
FROM table;