Question

I need a way to get true-false reply from SQL query that say to me: value in one column are the same or not?

Answer 1

This will work, if there are no null values in the column. Null values in the column are ignored by this solution.

SELECT 
    CASE 
        WHEN MIN(Column1) <> MAX(Column1) THEN 'FALSE' 
        ELSE 'TRUE' 
    END 
FROM MyTable

I tested this with SQL Server when the datatype of Column1 is varchar and int.