android - 如何在游标查询中使用 group by 子句？

Question

我想在以下游标查询的“helper.TX_NAME”列上使用 group by 子句生成合并报告。

String[] columns = {VivzHelper.UID, helper.TX_NAME, helper.TX_PARTICULARS, helper.TX_AMOUNT, helper.TX_DATE};

Cursor c = db.query(VivzHelper.TX_TABLE, 
    columns, 
    helper.TX_ID + "='" + name + "' AND " + helper.TX_DATE + " BETWEEN '" + datefrom.from_date + "' AND '"  + dateto.to_date + "  ' ", 
    null, 
    null, 
    null, 
    null, 
    null);

Answer 1

要获取每个日期和姓名组合的输出行，按这些列分组:

SELECT Date,
       Name,
       SUM(Amount) AS Amount
FROM TxTable
GROUP BY Date,
         Name

在Java中，只需将各个部分放入适当的参数中即可:

String[] columns = {
    helper.TX_NAME,
    "SUM("+helper.TX_AMOUNT+") AS "+helper.TX_AMOUNT,
    helper.TX_DATE
};
db.query(VivzHelper.TX_TABLE,
         columns,
         helper.TX_ID + "= ? AND " + helper.TX_DATE + " BETWEEN ? AND ?",
         new String[] { name, datefrom.from_date, dateto.to_date },
         helper.TX_NAME + ", " + helper.TX_DATE,
         null, null);