Question

I was wondering what types of things usually vary between SQL implementations when looking at the query statements. One thing that I thought was the use of IS NULL in the WHERE clause. See bleow for example. I’m writing a query statement parser that handles the statement and queries in a custom language and need to account for most of the general differences between the more widely used SQL products.

Oracle Syntax:

SELECT * FROM TABLE WHERE COLUMN_A IS NULL 
SELECT * FROM TABLE WHERE COLUMN_A IS NOT NULL

MySQL Syntax?

SQL Server Syntax?

Answer 1

I’m not sure you’re going to find a definitive list of all differences. A few things I can think of off the top of my head:

• MySQL uses LIMIT while SQL Server uses TOP.
• SQL Server is much stricter on GROUP BY operations than MySQL, requiring that all non-aggregated columns from the SELECT appear in the GROUP BY clause.
• SQL Server supports a proprietary UPDATE FROM and DELETE FROM syntax that goes beyond the ANSI standard.
• Functions that exist in one system but not another. MySQL has FIND_IN_SET and GROUP_CONCAT that don’t exist in SQL Server. Likewise, SQL Server has ROW_NUMBER() that doesn’t exist in MySQL.