SQL Server Express version is a free SQL Server database system that you can Download, Distribute and use for Development, Training & Study purpose. This Express version is targeted for Small scale Applications/Companies, Students, etc.
This Express version provides almost all major features of the full, paid version of the SQL Server, but is limited to the Database Engine itself.
–> Here are some of its Limitations:
1. Max size of a DataBase is set to 10 GB (but you can create multiple databases)
2. No SQL Agent
3. Single CPU utilization (can have multi cores)
4. Max 1 GB RAM allocation
5. Max 16 number of instances per server
6. MS BI features are not available for designing DW/BI workloads (SSIS/AS/RS)
You can also directly download the Express bits from here: