Why is query with phone = N'1234' slower than phone = '1234'?

Why is query with phone = N'1234' slower than phone = '1234'?

sql sql-server query-performance

sql

Why is there a HUGE performance difference between temp table and subselect

sql sql-server-2008-r2 subquery query-performance temp-tables

sql

How do NULL values affect performance in a database search?

sql database oracle database-performance query-performance

sql

How to improve performance on a clustered index seek

sql sql-server query-performance sql-execution-plan

sql

SQLite: Should LIKE 'searchstr%' use an index?

sql sqlite cocoa sql-like query-performance

sql

Conditional aggregation performance

sql sql-server query-performance conditional-aggregation

sql

DISTINCT with PARTITION BY vs. GROUPBY

sql sql-server group-by distinct query-performance

sql