Add SQL series from J2Team (#9594)

* Add new SQL series

* Update free-courses-vi.md

minor adjustment

courses/free-courses-vi.md

@@ -255,6 +255,7 @@
 * [Học SQL Cơ Bản](https://www.youtube.com/playlist?list=PLE1qPKuGSJaDkQQB5vK7t7-PRIVjtqeHB) - Thân Triệu
 * [Học SQL Cơ Bản](https://www.codehub.com.vn/Hoc-SQL) - Codehub
 * [Lập trình SQL Server căn bản](https://tedu.com.vn/khoa-hoc/lap-trinh-sql-server-can-ban-6.html) - TEDU
+* [SQL](https://www.youtube.com/playlist?list=PLiyVagO7GfBEOReFCMbcffzkgfWaGl-AN) - J2Team
 * [SQL Cơ Bản](https://www.youtube.com/playlist?list=PL33lvabfss1xnFpWQF6YH11kMTS1HmLsw) - Kteam