Counting null and missing values using RODBC package

I am working to create a a matrix of missingness for a SQL database consisting of 5 tables and nearly 10 years of data. I have established ODBC coectivity and am using the RODBC package in R as my working environment. I am trying to write a function that will output a count of rows for each year for each table, a count and percent of null values (values not present) in a given year for a given table, and a count and percent of missing (questions skipped/not answered) values for a given table. I have written the code below, trying to get it to work on one variable then tuing it into a function once it works. However, when I run this code, the count for total, missing and null values are all the same and the percent of course is 1. I am not getting any error messages. I am not sure where the issue lies and it is important to distinguish between missing and null for this project. Any insight is much appreciated.

test1 <- sqlQuery(chael, "select [EVENT_YEAR] AS 'YEAR', COUNT(*) AS 'TOTAL',

     COUNT(CASE WHEN MOTHER_EDUCATION_TRENDABLE = 'NA' THEN 1 ELSE 0 END) AS 'NULL_VAL',
     COUNT(CASE WHEN MOTHER_EDUCATION_TRENDABLE = -1 THEN 1 ELSE 0 END) AS 'MISS_VAL'

              from [GA_CMH].[dbo].[BIRTHS]

              GROUP BY [EVENT_YEAR]
              ORDER BY [EVENT_YEAR]")

test1$nullpct<-with(test1, NULL_VAL/TOTAL)

test1$misspct<-with(test1, MISS_VAL/TOTAL)