我昨天使用了完全相同的查询，今天工作正常，我对程序的流程做了一些更改，查询不再返回和行。
我的程序执行的第一个函数:
public void prepareSummary(Date startDate , Date endDate)
{
int getStartDay = getDayFromDate(startDate);
int getStartMonth = getMonthFromDate(startDate);
//
int getEndDay = getDayFromDate(endDate);
int getEndMonth = getMonthFromDate(endDate);
int getYear = getYearFromDate(startDate);
if(getStartMonth <= getEndMonth)
{
if(getStartMonth == getEndMonth)
{
if(getStartDay < getEndDay)
{
while(getStartDay <= getEndDay)
{
Calendar cal = Calendar.getInstance();
cal.set( getYear, getStartMonth, getStartDay);
Date queryStart = getStartOfDay(cal.getTime());
Date queryEnd = getEndOfDay(cal.getTime());
List<Object[]> res = getSumList(queryStart, queryEnd);
doQuery(res);
++getStartDay;
}
}
else
{
}
}
else
{
}
}
else
{
}
}
getSumList是这样的:
public List<Object[]> getSumList(Date start, Date end) {
String query = "";
query += "SELECT COUNT(s) pCount,"
+ "p.nameText,"
+ "g.nameText,"
+ "t.shiftID"
+ " FROM Sheets s , GradeNames g , SpecieNames p, ShiftTimes t"
+ " WHERE s.createdLocal > :start and s.createdLocal < :end"
+ " AND s.specieNameIndex = p.nameIndex "
+ " AND s.gradeNameIndex = g.nameIndex"
+ " AND s.shiftIndex = t.shiftIndex"
+ " GROUP BY p.nameText , g.nameText , t.shiftID";
Query q = em.createQuery(query);
q.setParameter("start", start);
q.setParameter("end", end);
return q.getResultList();
}
下一个函数此时无关紧要，因为没有执行任何操作，因为列表长度为零:
private void doQuery(List<Object[]> obj)
{
int length = obj.size();
String grade = null;
Long standingCount = (long) 0;
System.out.println("Length" + length);
for (int i = 0; i < length; ++i) {
// HAVE A LIST OF ALL ITEMS PULLED FROM DATABASE
Object[] tmpObj = obj.get(i);
Long tmpCount = (Long) tmpObj[0];
String tmpSpecieName = (String) tmpObj[1];
Double tmpThickness = Double.parseDouble(getSpecie().getThicknessFromSpecie(tmpSpecieName));
String tmpLength = getSpecie().getLengthFromSpecie(tmpSpecieName);
String tmpGradeName = (String) tmpObj[2];
String tmpShift = (String) tmpObj[3];
tmpSpecieName = getSpecie().getSpecieFromSpecie(tmpSpecieName);
//// END OF ALL ITEMS PULLED FROM DATABASE
if (grade != pullGradeName(tmpGradeName) && grade != null) {
System.out.println("Count:" + standingCount + "Grade:" + tmpGradeName + "--" + "Specie" + tmpSpecieName + "Shift:" + tmpShift + "Thickness:" + tmpThickness + "Length:" + tmpLength + "SpecieNAme:" + tmpSpecieName);
// do previous insert
grade = pullGradeName(tmpGradeName);
} else if (grade != pullGradeName(tmpGradeName) && grade == null) {
grade = pullGradeName(tmpGradeName);
} else if (grade == pullGradeName(tmpGradeName)) {
standingCount = standingCount + tmpCount;
}
System.out.println("Count:" + tmpCount + "Grade:" + tmpGradeName + "--" + "Specie" + tmpSpecieName + "Shift:" + tmpShift + "Thickness:" + tmpThickness + "Length:" + tmpLength + "SpecieNAme:" + tmpSpecieName);
}
}
检查生成的SQL和要查询的表。由于查询需要内部连接，如果其中一个表被清除，则不会返回任何结果。如果您想获得一个0计数，您需要使用外部连接语法，这在JPA中是不可能的，除非您使用对象级映射:
"SELECT COUNT(s) pCount,"
+ "p.nameText,"
+ "g.nameText,"
+ "t.shiftID"
+ " FROM Sheets s outer join s.specialNameIndex p,"
+ " outer join s.gradeNameIndex g, outer join s.shiftIndex t"
+ " WHERE s.createdLocal > :start and s.createdLocal < :end"
+ " GROUP BY p.nameText , g.nameText , t.shiftID";