Most real SQL questions are about which function this engine uses — running total, top row per group, dedup, pivot, upsert, JSON. Every database does these but spells them differently. This site puts each task on one page with the exact syntax per dialect, side by side.
Every recipe covers MySQL (8+), PostgreSQL, SQLite (3.25+), BigQuery, Snowflake and DuckDB, with the version requirements and traps. For date/time across dialects, see our companion site datesql.