使用SQL查询的Android Where子句问题

本文介绍了使用SQL查询的Android Where子句问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有以下的code创建我的表。我将数据插入到它，看起来像这样

I have the following code that creates my table. I insert data into it that looks like this

_id     date     recordName     total
--------------------------------------
7      2011     TestMaxRecord     5

Java的code：

Java code:

public static final String KEY_ROWID = "_id";   
public static final String KEY_DATE = "date";
public static final String KEY_TOTAL = "total";
public static final String KEY_RECORD_NAME = "recordName";

private static final String DATABASE_CREATE_RECORDS = "create table " + DATABASE_TABLE_RECORDS + " (" 
+ KEY_ROWID + " integer primary key autoincrement, " 
+ KEY_DATE + " text not null, "
+ KEY_RECORD_NAME + " text not null, "
+ KEY_TOTAL + " text not null);";

public Cursor getRecord(String name) throws SQLException {
  return mDb.query(true, DATABASE_TABLE_RECORDS, new String[] {KEY_ROWID, KEY_DATE, KEY_RECORD_NAME, KEY_TOTAL}, KEY_RECORD_NAME + " = " + name, null, null, null, null, null);
}

据每次抛出一个异常，其中name =TestMaxRecord（尽管那里是在那里的数据），出现以下错误

It throws an exception every time where name = "TestMaxRecord" (despite there being data in there) with the following error

android.database.sqlite.SQLiteException：没有这样的列：TestMaxRecord：在编制：SELECT DISTINCT _id，日期，recordName，共有来自记录中，其中recordName = TestMaxRecord

看起来像是对我说，它正在寻找一个列标题 TestMaxRecord 。我是一个Android新手，但（这是虽然使用INT）复制这部分pretty的多少完全由一个例子。是否有使用int和字符串您的查询之间的差异？

Which looks like to me that it is looking for a column title TestMaxRecord. I am an android newbie but copied this portion pretty much exactly from an example (it was using int though). Is there a difference between using int and Strings on your query?

推荐答案

您需要把单引号围绕价值，否则就会把它当作一列。

You need to put single quotes around the value, otherwise it will treat it as a column.

KEY_RECORD_NAME + " = '" + name + "'"

注：该解决方案是开放的SQL注入，你应该使用参数占位符，并通过 selectionArgs两个参数传递的值：

public Cursor getRecord(String name) throws SQLException {
  return mDb.query(true, 
    DATABASE_TABLE_RECORDS, 
    new String[] {KEY_ROWID, KEY_DATE, KEY_RECORD_NAME, KEY_TOTAL}, 
    KEY_RECORD_NAME + " = ?",
    new String[] {name},
    null, null, null, null);
}

另外，考虑<$c$c>SQLiteQueryBuilder

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TestMaxRecord