Convert a String to a Date in SQL (per Dialect)

Turning a text value into a real DATE you can do math on.

ISO format (‘2024-01-15’)

-- MySQL
SELECT CAST('2024-01-15' AS DATE);

-- PostgreSQL
SELECT '2024-01-15'::date;              -- or CAST('2024-01-15' AS DATE)

-- BigQuery
SELECT DATE('2024-01-15');

-- Snowflake
SELECT '2024-01-15'::date;              -- or TO_DATE('2024-01-15')

-- SQLite
SELECT DATE('2024-01-15');              -- ISO strings only

-- DuckDB
SELECT DATE '2024-01-15';              -- or '2024-01-15'::DATE

Custom format (e.g. ‘15/01/2024’)

-- MySQL
SELECT STR_TO_DATE('15/01/2024', '%d/%m/%Y');

-- PostgreSQL
SELECT TO_DATE('15/01/2024', 'DD/MM/YYYY');

-- BigQuery
SELECT PARSE_DATE('%d/%m/%Y', '15/01/2024');

-- Snowflake
SELECT TO_DATE('15/01/2024', 'DD/MM/YYYY');

-- DuckDB
SELECT strptime('15/01/2024', '%d/%m/%Y')::DATE;

Gotchas: SQLite has no format parser — it only understands ISO-8601 (YYYY-MM-DD); reformat the string first (e.g. with substr) or store ISO. Format tokens differ by family: MySQL/BigQuery use strftime-style (%d/%m/%Y), while Postgres/Snowflake use template patterns (DD/MM/YYYY). Casting a string with the wrong order (DMY vs MDY) silently gives the wrong date — always pass an explicit format for non-ISO input.