Here are top online resources where you can do practice of MySQL without install it on your laptop.
Useful string functions for smart SQL developers to write better queries. Useful to read now.
I have given three ideas to improve SQL performance in this post. Quickly you can implement in your project.
SQL DATE and Time comparison popular styles and SQL queries useful to read for your project.
SQL Order of execution is sequence of steps. The database executes each Query in a particular order. Read more.
SQL ALTER statement you can use to add columns to existing TABLE in RDBMS. Not only TABLE you can read all database object where you can use ALTER.
Ordering the SQL result is possible by giving DESC or ASC in your query. These must be used along with ORDER BY clause. Read more.
Having Vs Where clause in SQL real usage is to filter rows on aggregate totals. Read more.
SQL Queries you can run and test in your project to update or modify existing rows in a Table.
Performance areas in DB2 must to improve.
These are best practices and guide lines to review any SQL program. The example given here is for COBOL.
SQL queries useful to check if Table exists or not in Oracle database., You can try these queries in SQL developer to know if Table is created by DBA or database administrator.