Neues Problem mit SQL Abfrage

SELECT kd_nummer,
       SUM(DECODE(EXTRACT(MONTH FROM rgdatum),EXTRACT(MONTH FROM SYSDATE),netto,0)) SumAktMontat,
       SUM(netto) SumJahr
FROM rechnung
WHERE rgdatum >= TRUNC(SYSDATE,'YYYY')  
AND status != 3 
AND gs != 1
GROUP BY kd_nummer
ORDER BY kd_nummer

SELECT kd_nummer,
       SUM("wenn" DECODE(MONTH(rgdatum) = MONTH(SYSDATE) "dann" netto "sonst" 0) SumAktMontat,  
       SUM(netto) SumJahr
FROM rechnung
WHERE YEAR(rgdatum) = YEAR(SYSDATE)
AND status != 3 
AND gs != 1
GROUP BY kd_nummer
ORDER BY kd_nummer

SELECT t.kd_nummer, SUM(m.netto) AS 'month', SUM(y.netto) AS 'year'  
FROM table t
  JOIN table m ON (t.kd_nummer = m.kd_nummer)
  JOIN table y ON (t.kd_nummer = y.kd_nummer)
WHERE
  ( MONTH(m.rgdatum) = MONTH(NOW()) AND YEAR(m.rgdatum) = YEAR(NOW()) ) AND
  YEAR(y.rgdatum) = YEAR(NOW())
GROUP BY t.kd_nummer

SELECT kd_nummer, 
       SUM(IF(MONTH(rgdatum) = MONTH(NOW()), netto, 0)) AS SumAktMontat, 
       SUM(netto) AS SumJahr 
FROM rechnung 
WHERE YEAR(rgdatum) = YEAR(NOW()) 
AND status != 3  
AND gs != 1 
GROUP BY kd_nummer 
ORDER BY kd_nummer