SQL Server Express is a free edition of SQL Server ideal for developing and powering desktop, web and small server applications.
SQL Server Express 2012 Versions
SQL Server Express with Tools (with LocalDB, Includes the database engine and SQL Server Management Studio Express)
Need to learn SQL Server Management? This contains everything needed to install and configure SQL Server as a database server.
SQL Server Management Studio (Tools only)
Need to learn SQL Server development? This package does not contain the database, only the tools to manage SQL Server instances, including LocalDB, SQL Express, SQL Azure, etc. Use this if you already have the database and only need the management tools.
SQL Server Express LocalDB (MSI installer)
Need to embed SQL Server Express into an application? New to the Express family, LocalDB is a lightweight version of Express that has all its programmability features yet runs in user mode and has a fast, zero-configuration installation and short list of pre-requisites.
SQL Server Express with Advanced Services (contains the database engine, Express Tools, Reporting Services, and Full Text Search)
Want to experience all the features of SQL Server Express? This package contains all the components of SQL Server Express. This is a larger download than “Express with Tools” as it also includes both Full Text Search and Reporting Services.
SQL Server Express (Containing only the database engine)
Already have the tools, just need the database server? This is the core Express database server. Use this if you need to accept remote connections or administer remotely.