Correct date on invoices

DECLARE @currentDate VARCHAR(14),@shiftn AS INT
SET @currentDate=CAST(datepart(yyyy,getdate()) AS VARCHAR) + '/' + CAST(datepart(mm,getdate()) AS VARCHAR) + '/' + CAST(datepart(dd,getdate()) AS VARCHAR)
SELECT top 1 @shiftn=shiftnum FROM tillpost WHERE date>@currentDate AND date<getdate()

IF NOT @shiftn IS NULL
UPDATE invoices
SET DATE=@currentDate + ' ' + CAST(datepart(hh,DATE) AS VARCHAR) + ':' + CAST(datepart(mi,DATE) AS VARCHAR) + ':' + CAST(datepart(ss,DATE) AS VARCHAR),
shiftnum=@shiftn
WHERE date>getdate()
IF NOT @shiftn IS NULL
SELECT top 1 'COMPLETED SUCCESSFULLY, INVOICES MOVED TO SHIFTNUM: ' + CAST(@shiftn AS VARCHAR) AS Outcome FROM invoices
ELSE
SELECT top 1 'NO TILLSHIFTS ON THE CURRENT DATE: ' + @currentDate AS Outcome FROM invoices