Question

Im a noob to android and I am trying to run a query on my database to return a single string value from my table. I have done this successfully in one query by selecting my row id using a long. Shown here:

public String getHotness(long l) throws SQLException{
    // TODO Auto-generated method stub
    String[] columns = new String[]{  KEY_ROWID, KEY_NAME, KEY_HOTNESS };
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" + l, null, null, null, null);
    if (c != null){
        c.moveToFirst();
        String hotness = c.getString(2);
        return hotness;
    }
    c.close();
    return null;
}

But now i have to query another table using a string, but when i execute this query i get a SQLException.

public String getSingleQty(String aCoin) throws SQLException{
    // TODO Auto-generated method stub
    String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE};     
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=" + aCoin, null, null, null, null); //<--this causes exception
    String result = "";

    if (c != null){
        c.moveToFirst();
        result= c.getString(2);
        c.close();
        return result;
    }
    c.close();
    return null;

I don’t understand why this is occurring. I used the same format for both tables. Any help is greatly appreciated.

Answer 1

Since aCoin is being passed as a string to the query, it has to be wrapped by apostrophes. Corrected fragment of code:

Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "='" + aCoin + "'", null, null, null, null);

or (if the syntax suit you better) try it that way:

Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=?", new String[] {aCoin}, null, null, null);