I don't know why you make it in so complikated way.

Below you can find my version of your procedure.

CREATE PROCEDURE [dbo].[ColumnDependency2]

@TableName VARCHAR(128) ,

@Determinant VARCHAR(128) ,

@Dependent VARCHAR(128)

AS

Declare @SQL VarChar(MAX);

SELECT @SQL = 'WITH all_ AS (

SELECT '+@Determinant+'

,'+@Dependent+'

,count(*) cnt

FROM '+@TableName+'

GROUP BY '+@Determinant+'

,'+@Dependent+'

)

, fraction_ AS (

SELECT '+@Determinant+'

,max(cnt) support_count

,sum(cnt) frac_cnt

FROM all_

GROUP BY '+@Determinant+'

)

SELECT v.'+@Determinant+'

,'+@Dependent+'

,cnt [Dependeny Counts]

,case when cnt < support_count then ''Violation Percentage''

ELSE ''Support Percentage''

end [Dependency type]

,CAST(CAST(cnt AS DECIMAL ) / frac_cnt * 100 AS DECIMAL (5, 2)) AS PercentViolation

FROM all_ v

,fraction_

WHERE fraction_.'+@Determinant+' = v.'+@Determinant+'

ORDER BY 1, 3 DESC ';

Print @SQL

Exec (@SQL)

and execution:

Exec ColumnDependency2

@TableName = 'Addresses',

@Dependent = 'StateProvinceName',

@Determinant = 'CountryRegionCode '

😉