Does PostgreSQL have a DATEADD function?

No — PostgreSQL doesn't need one, because it treats INTERVAL values as first-class operands you can add or subtract directly, e.g. order_date + INTERVAL '7 days'. DATEADD() is SQL Server syntax and raises a syntax error against PostgreSQL.

Why does DATEDIFF give different answers in MySQL and SQL Server?

Because the two functions have different signatures. MySQL's DATEDIFF(expr1, expr2) always returns whole days as expr1 minus expr2, with no unit argument. SQL Server's DATEDIFF(datepart, startdate, enddate) takes a unit first and counts datepart boundaries crossed, which can differ from a literal day count.

How do I get the current date in SQLite?

date('now') returns the current date as text, and datetime('now') returns the current date and time — SQLite has no dedicated NOW() function or native date type; both are string-producing functions.

What date format does BigQuery use for DATE_ADD?

BigQuery's DATE_ADD(date_expression, INTERVAL int64 date_part) mirrors MySQL's DATE_ADD syntax closely — DATE_ADD(order_date, INTERVAL 7 DAY) works nearly unchanged if you're porting from MySQL.

Is there a date function that works the same across all five dialects?

No single function call works unmodified everywhere covered here — even getting “today's date” is five different function calls. ISO 8601 date literals ('2026-01-13') are the closest thing to portable, since every dialect parses that literal the same way even though the functions operating on it don't match.

SQL Dialects

SQL Date and Time Functions Across Dialects

By Sharon Ben-Moshe · August 8, 2026 · 2 min read

Sharon Ben-Moshe is the founder of sqlfmt, a browser-based SQL formatter and validator with misspelled-keyword suggestions across PostgreSQL, MySQL, SQLite, SQL Server, and BigQuery.

“Add 7 days” is DATEADD in SQL Server, DATE_ADD in MySQL and BigQuery, a raw interval in PostgreSQL, and a modifier string in SQLite — the same operation, four unrelated shapes. Here's the working syntax for each dialect's core date functions.

Quick answer

Adding or subtracting time uses INTERVAL arithmetic in PostgreSQL, DATE_ADD()/DATE_SUB() in MySQL and BigQuery, DATEADD() in SQL Server, and date('now', modifier) strings in SQLite — five dialects, five unrelated syntaxes for the same three operations: add or subtract an interval, get the current date, and compute the difference between two dates.

SQL Date and Time Functions Across Dialects

Quick answer

FAQs

Does PostgreSQL have a DATEADD function?

Why does DATEDIFF give different answers in MySQL and SQL Server?

How do I get the current date in SQLite?

What date format does BigQuery use for DATE_ADD?

Is there a date function that works the same across all five dialects?

SQL UPSERT Across Dialects: ON CONFLICT, ON DUPLICATE KEY, and MERGE

SQL Pagination Across Databases: LIMIT, TOP, and OFFSET-FETCH Compared

SQL NULL-Handling Functions Across Dialects: COALESCE, ISNULL, and IFNULL

Key takeaways

Adding or subtracting time

Getting the current date or timestamp

Computing the difference between two dates

Formatting a date as a string

Quick answer

FAQs

Does PostgreSQL have a DATEADD function?

Why does DATEDIFF give different answers in MySQL and SQL Server?

How do I get the current date in SQLite?

What date format does BigQuery use for DATE_ADD?

Is there a date function that works the same across all five dialects?

Keep reading

SQL UPSERT Across Dialects: ON CONFLICT, ON DUPLICATE KEY, and MERGE

SQL Pagination Across Databases: LIMIT, TOP, and OFFSET-FETCH Compared

SQL NULL-Handling Functions Across Dialects: COALESCE, ISNULL, and IFNULL

Key takeaways

Adding or subtracting time

Getting the current date or timestamp

Computing the difference between two dates

Formatting a date as a string

Related reading