哪位高手可以帮忙解释一下SQL中的意思

SELECT * FROM WF_INSTANCE A, WFV_TASK B, G_PRJ_XMXX C
WHERE A.INSTID = B.INSTID [%=if(isSuperAdmin(curUser()),""," AND ((B.FINISHUSER IS NOT NULL AND B.FINISHUSER='"+curUser()+"' OR B.FINISHUSER IS NULL AND B.EXECUSER IS NOT NULL AND B.EXECUSER='"+curUser()+"') OR (B.FINISHUSER IS NULL AND B.EXECUSER IS NULL AND ((B.EXECROLE IS NOT NULL AND "+concatCols("wfdata","B.ROLESUBSYS,'.',B.EXECROLE")+" IN ("+userRoles(curUser(),null,",",true)+")) OR B.EXECROLE IS NULL)))" + if(hasRole('appzjgg', 'SJ_GBKZ') || hasRole('appzjgg', 'SJ_JB'), " AND C.CORG_ IN (select ORGANISEID from ORGANISE where PARENTID = '" + curOrg() + "')", ""))%]
ORDER BY B.ARRIVETIME DESC