This document summarizes key differences in functions between Microsoft SQL Server and MySQL. It covers TOP-N queries to limit results, string functions like LEN, CONCAT and SUBSTRING, and datetime functions such as NOW() and DATEDIFF() to get dates and calculate differences between dates. Examples are provided for each to demonstrate the syntax for the equivalent functions in each database.

1. 21st Meeting
MySQL and SQL Server
9:00PM – 10:00 PM – May 11, 2019
Lai Trung Minh Duc | DucLTM@outlook.com
Microsoft Student Partners Vietnam | Analytics Vietnam Community
Lai Trung Minh Duc | May 2019 | DucLTM@outlook.com 1

2. Contents
• TOP-N
• STRING functions
• DATETIME functions

3. TOP-N
MS SQL Server
SELECT TOP n <columns>
FROM <tablename>
ORDER BY key ASC
MySQL
SELECT <columns>
FROM <tablename>
ORDER BY key ASC
LIMIT n

4. STRING functions | LEN
MS SQL Server
SELECT LEN (<>)
FROM table
MySQL
SELECT CHARACTER_LENGTH(<>)
FROM table

5. STRING functions | CONCAT
MS SQL Server
SELECT (‘A’ + ‘B’ + ‘C’)
MySQL
SELECT CONCAT (‘A’, ‘B’, ‘C’)

6. STRING functions | SUBSTRING
MS SQL Server
SUBSTRING (input, start, length)
MySQL
SUBSTRING (input FROM start FOR
length)

7. DATETIME functions | NOW()
MS SQL Server
GETDATE()
MySQL
NOW()

8. DATETIME functions | DATEDIFF()
MS SQL Server
SELECT DATEDIFF(m,'2019-05-
01','2019-07-31')
MySQL
SELECT TIMESTAMPDIFF(DAY,
'2019-05-01','2019-07-31’).
SELECT DATEDIFF('2019-05-
01','2019-07-31’)

9. THANK YOU
Lai Trung Minh Duc | May 2019 | DucLTM@outlook.com 9