COUNT（）中加条件

SELECT D.CODE,PROJECT.SUB_COUNT,PROJECT.DONE_COUNT,PROJECT.ORIGIN FROM PUB_DEPARTMENT D,
(SELECT COUNT(P.PROJECT_ID) SUB_COUNT,SUM(CASE(P.STATE) WHEN 7 THEN 1 ELSE 0 END) DONE_COUNT,
SUBSTR(P.DEPARTMENT_CODE,1,6)
SUB_CODE,P.ORIGIN FROM PM_COM_PROJECT P
WHERE P.CLASS_NAME = 'MainTask'
AND P.STATE >= '5'
GROUP BY SUBSTR(P.DEPARTMENT_CODE,1,6),P.ORIGIN) PROJECT
WHERE D.CODE = PROJECT.SUB_CODE(+)
AND D.CODE LIKE '0601%'
AND D.TREE_LEVEL = 3
AND LENGTH(D.CODE) = 6

上面这段SQL中SUM(CASE(P.STATE) WHEN 7 THEN 1 ELSE 0 END)
就是变相的实现了COUNT（）中传条件，

就是说P.STATE为7时才在SUM里统计为1，否则统计为0