MySQL, SQL Server & Access Functions (Overview)

Database-specific functions — high-level map

Core SQL (SELECT, JOIN, GROUP BY) works everywhere. String, date, and math helper functions differ by vendor.

Check your database docs when a function fails — COALESCE is portable; GETDATE() vs NOW() vs CURRENT_DATE is not.

Real-life example: Functions are regional dialects — 'elevator' vs 'lift' — same idea, different word on MySQL vs SQL Server.

• MySQL: CONCAT(), IFNULL(), NOW(), DATE_FORMAT()
• SQL Server: + concat, ISNULL(), GETDATE(), FORMAT()
• Access: & concat, NZ(), Now(), Format()
• All: COUNT, SUM, AVG, MIN, MAX, COALESCE (mostly)

-- MySQL
SELECT CONCAT(full_name, ' - ', DATE_FORMAT(NOW(), '%Y-%m-%d')) AS label FROM students;

-- SQL Server
SELECT full_name + ' - ' + CONVERT(VARCHAR, GETDATE(), 23) AS label FROM students;

-- PostgreSQL / SQLite (portable)
SELECT full_name || ' - ' || DATE('now') AS label FROM students;