My SQL statement in SQL Server looks like this:

```
DECLARE @forecastYear AS varchar(5)
    SET @forecastYear = '2020'
DECLARE @versionName AS varchar(25)
    SET @versionName = '20201113_wk'
DECLARE @currentMonth AS varchar(2)
    SET @currentMonth = (SELECT current_fc_month FROM tbl_current_month)
 SELECT f.record_id
     , u.it_ops_j_level_abbr_nm 
     , f.owner_nm 
     , f.unit_cd 
     , f.tbm_cd 
     , f.tower_nm 
     , f.description_txt 
     , f.comment_txt 
     , f.cost_pool_nm 
     , f.glac_nr 
     , f.glac_nm 
     , f.initiative_nm 
     , f.priority_nm 
     , f.growth_nm 
     , f.it_vendor_nm 
     , f.jan_amt 
     , f.feb_amt 
     , f.mar_amt 
     , f.apr_amt 
     , f.may_amt 
     , f.jun_amt 
     , f.jul_amt 
     , f.aug_amt 
     , f.sep_amt 
     , f.oct_amt 
     , f.nov_amt 
     , f.dec_amt 
  FROM tbl_new_forecast f
       INNER JOIN tbl_unit_tree u
               ON f.unit_cd = u.dept_id 
 WHERE f.version_nm = @versionName 
   AND f.status_cd = 'Approved'
   AND f.entry_type = 'Forecast'
   AND f.forecast_yr_id = @forecastYear 
   AND ABS(f.nov_amt)+ABS(f.dec_amt) <> 0

```

What I want to do is change the last statement in the WHERE clause based on the value in `@currentMonth`.
Therefore, if `@currentMonth` = '3' then the last statement would read

```
AND ABS(f.mar_amt)+ABS(f.apr_amt)+ABS(f.may_amt) <> 0

```

If `@currentMonth` = '7' then it would read

```
AND ABS(f.jul_amt)+ABS(f.aug_amt)+ABS(f.sep_amt) <> 0

```

I'm having a hard time figuring out how to accomplish this, because I get a SQL error with this syntax:

```
AND CASE 
      WHEN @currentMonth = '10' THEN ABS(f.oct_amt)+ABS(f.nov_amt)+ABS(f.dec_amt) <> 0
    END

```

Any help is appreciated!