Quick questions:

1. Why are you using Dynamic SQL when a normal query would be enough?

2. Why aren't you parametrizing your Dynamic SQL leaving it open to SQL Injection?

3. Why are you using IN for a single value?

Static SQL example:

SELECT @MinBoundary = Convert(DateTime, MIN(PRV.value))

FROM sys.partition_functions AS PF

JOIN sys.partition_parameters AS PP

ON PF.function_id = PP.function_id

JOIN sys.types AS T1

ON T1.system_type_id = PP.system_type_id

JOIN sys.types AS T2

ON T2.user_type_id= PP.user_type_id

JOIN sys.partition_range_values AS PRV

ON PP.function_id = PRV.function_id

AND PP.parameter_id = PRV.parameter_id

WHERE PF.name = 'WBC_' + @TableName + '_pf'

PRINT @MinBoundary

Dynamic SQL example parametrized query:

DECLARE @MinBoundary DateTime, @s-2 nvarchar(max)

declare @DBName sysname, @TableName sysname

select @DBName = 'MyDB', @TableName = 'MyTable'

select @s-2 = '

SELECT @MB=Convert(DateTime, MIN(PRV.value))

FROM sys.partition_functions AS PF

JOIN sys.partition_parameters AS PP

ON PF.function_id = PP.function_id

JOIN sys.types AS T1

ON T1.system_type_id = PP.system_type_id

JOIN sys.types AS T2

ON T2.user_type_id= PP.user_type_id

JOIN sys.partition_range_values AS PRV

ON PP.function_id = PRV.function_id

AND PP.parameter_id = PRV.parameter_id

WHERE PF.name IN (''WBC_'' + @TN + ''_pf'')'

print @s-2

EXECUTE sp_executesql @s-2, N'@MB DateTime OUTPUT, @TN sysname', @MB=@MinBoundary OUTPUT, @TN=@TableName

PRINT @MinBoundary