Finding duplicates with SQL?

Suppose Col1 is the field name for which you want to find duplicates:

Select Col1, Count(Col1) as count
from table1
group by Col1
having Count(Col1) > 1

.

Rounding a number to 2 decimal places in SQL

Use T-SQL Convert Function.

Select convert ( decimal(8,2) , 9.4125 )

Output: 9.41

Difference between Varchar and Char data types?

Varchar is a variable length character data type whereas Char is a fixed length character data type. Because Varchar is a variable length data type therefore its size is the actual length of the data entered and not the maximum size of the column