Question

我想从表中使用按钮点击的条件检索最小余额。以下是我的代码它不工作PLZ给我解决方案。谢谢提前..

smname = spn_mname.getSelectedItem().toString().trim();

yname = spn_yname.getSelectedItem().toString().trim();

scno = spn_count.getSelectedItem().toString().trim();

String dbsyname = null, dbsmname = null, dbsycolor = null, dbscount = null, dbsrqty = null, dbsdqty = null, dbsbaln = null;
DataBaseHelper dbh = new DataBaseHelper(StockActivity.this);

SQLiteDatabase db = dbh.getReadableDatabase();

Cursor cursor = db.rawQuery("SELECT MIN(Balance) FROM stocktable",null);
if (cursor.moveToFirst()) {
    do {
        dbsmname = cursor.getString(cursor.getColumnIndex("Millname"));
        dbsyname = cursor.getString(cursor.getColumnIndex("Yarnname"));
        dbscount = cursor.getString(cursor.getColumnIndex("Counttno"));

        if (dbsmname.equals(smname) 
                && bsyname.equals(syname)
                && dbscount.equals(scno)) {
            dbsbaln = cursor.getString(cursor.getColumnIndex("Balance"));
        }

    } while (cursor.moveToNext());

    edtrqty.setText(dbsbaln);
}

Answer 1

您只在查询中选择了MIN（余额）并尝试访问Millname，Counttno以及光标上的其他值，它将抛出异常。

尝试以下解决方案

    Cursor cursor = db.rawQuery("SELECT MIN(Balance) balance as  FROM stocktable 
 where Millname=? AND bsyname=? AND dbscount=?",new String[]{smname,syname,scno});
  if (cursor.moveToFirst()) {
      do {
            dbsbaln = cursor.getString(cursor.getColumnIndex("balance"));
          }

      } while (cursor.moveToNext());
        edtrqty.setText(dbsbaln);

Answer 2

以下代码完美运作......

Cursor cursor = db.rawQuery（“SELECT MIN（Balance）AS balance FROM”+ DataBaseHelper.stocktable +“WHERE Millname =？AND Yarnname =？AND Counttno =？”，new String [] {smname，syname，scno }）;

            if (cursor.moveToFirst()) {
                do {
                    dbsbaln = cursor.getString(cursor
                            .getColumnIndex("balance"));

                } while (cursor.moveToNext());
                edtrqty.setText(dbsbaln);
            }

使用eclipse开发应用程序

2 个答案: