android - Android sqlite where 子句

Question

如何使这条线工作？

return ourDatabase.rawQuery("SELECT * FROM GL_" + tablename + " WHERE " + KEY_GROUP_T + " = " + grp + " ORDER BY " + KEY_NAME_T + " COLLATE NOCASE", null);

04-23 17:58:26.701：E/AndroidRuntime(9212)：原因：android.database.sqlite.SQLiteException：没有这样的列：Baked_Goods：，编译时：SELECT * FROM GL_table4 WHERE grlist_group = Baked_Goods ORDER BY grlist_name COLLATE NOCASE

这条线正在工作，但我想用 rawQuery 来做：

return ourDatabase.query("GL_" + tablename, columns, KEY_GROUP_T + "= ?" , new String[]{grp}, null, null, null);

Answer 1

要完成这项工作，您必须在字符串周围加上单引号。例子：

return ourDatabase.rawQuery("SELECT * FROM GL_" + tablename + " WHERE " + KEY_GROUP_T + " = '" + grp + "' ORDER BY " + KEY_NAME_T + " COLLATE NOCASE", null);

添加

Waqas 有一个好处，如果grp取自用户的输入，他正在防止SQL 插入攻击。如果您总是定义grp，那么这不是关键，而是良好的做法。

Answer 2

改变这个：

return ourDatabase.rawQuery("SELECT * FROM GL_" + tablename + " WHERE " +
KEY_GROUP_T + " = " + grp + " ORDER BY " + KEY_NAME_T + " COLLATE NOCASE", null);

对此：

return ourDatabase.rawQuery("SELECT * FROM GL_" + tablename + " WHERE " +
KEY_GROUP_T + " = ? ORDER BY " + KEY_NAME_T + " COLLATE NOCASE", new String[]{grp});

Answer 3

尽管单引号方法是正确的，但您可以提高查询速度，并提高可读性，并且如果您这样做，您不会忘记单引号：

String [] selectionArgs = {String.valueOf(grp)};
ourDatabase.rawQuery("SELECT * FROM GL_" + tablename + " WHERE " + KEY_GROUP_T + " = ?" + " ORDER BY " + KEY_NAME_T + " COLLATE NOCASE", selectionArgs);