Suppress Database Project errors and warnings in visual studio 2010
Updated answer
In VS 11+ the option has moved to Tools > Options > SQL Server Tools > General -> Errors and Warnings (set to 0 to get get a single error line)
You can exclude the project from the build configuration to avoid build failure.
For older versions
Options -> Database Tools -> Database Errors and Warnings -> set the maximum at 0 and from now on the error window will have a single entry that will say something like
Error 1 The maximum number of 0 errors has been reached. 76 total errors, 0 total warnings, and 0 total messages were encountered.
Just had this problem in Visual Studio 2015.
Halfway along the header of the Error List panel, there is a (unnamed) dropdown with values 'Build + Intellisense', 'Build Only', 'Intellisense Only'. Mine was set to 'Build + Intellisense'. Changing it to 'Build Only' got rid of all the (200+) errors.
Select the file in the project:
example: projectDatabase\ddl\table_name.sql
on the Properties Window of the file set
Build Action : None.
While building it doesn't look in this files for errors or warnings.
To surppress a specific warning, go to project properties -> Build.
Type in the warning numbers (i.e. without 'SQL') in comma delimited format in field "Suppress Transact-SQL warnings:".