是否有任何选项可以选择金额,按月分组并计算金额。我试图获得每个月的总和并将其传递给ArrayList。 数据示例:
Amount Date
230 04/03/19
500 05/03/19
400 04/04/19
600 06/04/19
100 04/03/19
... ...
我的代码结构
private String CREATE_BILLS_TABLE = "CREATE TABLE " + TABLE_BILLS + "("
+ COLUMN_BILL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ COLUMN_BILL_USER_ID + " INTEGER,"
+ COLUMN_DESCRIPTION + " TEXT,"
+ COLUMN_AMOUNT + " INTEGER,"
+ COLUMN_DATE_STRING + " TEXT,"
+ COLUMN_COMPANY_NAME + " TEXT,"
+ COLUMN_CATEGORY + " TEXT,"
+ " FOREIGN KEY ("+COLUMN_BILL_USER_ID+") REFERENCES "+TABLE_USER+"("+COLUMN_USER_ID+"));";
public ArrayList<Bills> getDateByUserID(int userID){
SQLiteDatabase db = this.getReadableDatabase();
// sorting orders
ArrayList<Bills> listBillsDates = new ArrayList<Bills>();
Cursor cursor = db.query(TABLE_BILLS, new String[] { COLUMN_BILL_ID,
COLUMN_BILL_USER_ID, COLUMN_DESCRIPTION, COLUMN_AMOUNT, COLUMN_DATE_STRING, COLUMN_COMPANY_NAME, COLUMN_CATEGORY}, COLUMN_BILL_USER_ID + "=?",
new String[] { String.valueOf(userID) }, COLUMN_DATE_STRING, null, null, null);
if (cursor.moveToFirst()) {
do {
Bills bills = new Bills();
bills.setAmount(cursor.getInt(cursor.getColumnIndex(COLUMN_AMOUNT)));
bills.setDateString(cursor.getString(cursor.getColumnIndex(COLUMN_DATE_STRING)));
// Adding record to list
listBillsDates.add(bills);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
// return category list
return listBillsDates;
}
我相信基于以下方面的查询: -
SELECT sum(COLUMN_AMOUNT) AS Monthly_Total,substr(COLUMN_DATE_STRING,4) AS Month_and_Year
FROM TABLE_BILLS
WHERE COLUMN_BILL_USER_ID = 1
GROUP BY substr(COLUMN_DATE_STRING,4)
ORDER BY substr(COLUMN_DATE_STRING,7,2)||substr(COLUMN_DATE_STRING,4,2)
;
会产生你想要的结果: -
EG
使用以下方法来测试SQL: -
DROP TABLE IF EXISTS TABLE_BILLS;
CREATE TABLE IF NOT EXISTS TABLE_BILLS (
COLUMN_BILL_ID INTEGER PRIMARY KEY AUTOINCREMENT,
COLUMN_BILL_USER_ID INTEGER,
COLUMN_DESCRIPTION TEXT,
COLUMN_AMOUNT INTEGER,
COLUMN_DATE_STRING TEXT,
COLUMN_COMPANY_NAME TEXT,
COLUMN_CATEGORY TEXT)
;
-- Add the Testing data
INSERT INTO TABLE_BILLS (
COLUMN_BILL_USER_ID, COLUMN_DESCRIPTION, COLUMN_AMOUNT, COLUMN_DATE_STRING, COLUMN_COMPANY_NAME,COLUMN_CATEGORY)
VALUES
(1,'blah',230,'04/03/19','cmpny','category')
,(1,'blah',500,'05/03/19','cmpny','category')
,(1,'blah',400,'04/04/19','cmpny','category')
,(1,'blah',600,'06/04/19','cmpny','category')
,(1,'blah',100,'04/03/19','cmpny','category')
-- Extra data for another id to check exclusion
,(2,'blah',230,'04/03/19','cmpny','category')
,(2,'blah',500,'05/03/19','cmpny','category')
,(2,'blah',400,'04/04/19','cmpny','category')
,(2,'blah',600,'06/04/19','cmpny','category')
,(2,'blah',100,'04/03/19','cmpny','category')
;
SELECT sum(COLUMN_AMOUNT) AS Monthly_Total,substr(COLUMN_DATE_STRING,4) AS Month_and_Year
FROM TABLE_BILLS
WHERE COLUMN_BILL_USER_ID = 1
GROUP BY substr(COLUMN_DATE_STRING,4)
ORDER BY substr(COLUMN_DATE_STRING,7,2)||substr(COLUMN_DATE_STRING,4,2)
;
结果ID: -
然后可以转换上述内容以供SQLiteDatabase查询方法使用。所以你的方法可能是这样的: -
public ArrayList<Bills> getDateByUserID(int userID) {
SQLiteDatabase db = this.getReadableDatabase();
String tmpcol_monthly_total = "Monthly_Total";
String tmpcol_month_year = "Month_and_Year";
String[] columns = new String[]{
"sum(" + COLUMN_AMOUNT + ") AS " + tmpcol_monthly_total,
"substr(" + COLUMN_DATE_STRING + ",4) AS " + tmpcol_month_year
};
String whereclause = COLUMN_BILL_USER_ID + "=?";
String[] whereargs = new String[]{String.valueOf(userID)};
String groupbyclause = "substr(" + COLUMN_DATE_STRING + ",4)";
String orderbyclause = "substr(" + COLUMN_DATE_STRING + ",7,2)||substr(" + COLUMN_DATE_STRING + ",4,2)";
ArrayList<Bills> listBillsDates = new ArrayList<Bills>();
Cursor cursor = db.query(TABLE_BILLS, columns, whereclause,
whereargs, groupbyclause, null, orderbyclause, null);
if (cursor.moveToFirst()) {
do {
Bills bills = new Bills();
bills.setAmount(cursor.getInt(cursor.getColumnIndex(tmpcol_monthly_total)));
bills.setDateString(cursor.getString(cursor.getColumnIndex(tmpcol_month_year))); //<<<<<<<<<< NOTE data is MM/YY (otherwise which date to use? considering result will be arbrirtaryy)
// Adding record to list
listBillsDates.add(bills);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
// return category list
return listBillsDates;
}
ArrayList<Bills> myMonthlyTotals = mDBHelper.getDateByUserID(1);
Log.d("BILLSCOUNT","The number of bills extracted was " + String.valueOf(myMonthlyTotals.size()));
for (Bills b: myMonthlyTotals) {
Log.d("MONTHYLTOTAL","Monthly total for " + b.getDateString() + " was " + String.valueOf(b.getAmount()));
}
:-
04-14 11:58:25.876 16653-16653/? D/BILLSCOUNT: The number of bills extracted was 2
04-14 11:58:25.877 16653-16653/? D/MONTHYLTOTAL: Monthly total for 03/19 was 830
04-14 11:58:25.877 16653-16653/? D/MONTHYLTOTAL: Monthly total for 04/19 was 1000
根据评论,使用公认的date formats可以使底层SQL更简单,更有效。