具有多个参数的原始查询

Question

PREF_NAME，PREF_STATUS - 文字

它给了我这个错误：

07-02 14:08:07.457: E/AndroidRuntime(17295): android.database.sqlite.SQLiteException: near "?": syntax error: , while compiling: SELECT ? FROM ? WHERE ? = ?

我正在使用的代码是：

Cursor c = db.rawQuery("SELECT ? FROM ? WHERE ? = ?", new String[]{ PREF_STATUS,
   PREF_TABLE, PREF_NAME, assigned_pref_name });

Answer 1

根据documentation，你只能把“？”在where子句：

public Cursor rawQuery (String sql, String[] selectionArgs)

Parameters
sql the SQL query. The SQL string must not be ; terminated
selectionArgs   You may include ?s in where clause in the query, which will be replaced by the values from selectionArgs. The values will be bound as Strings.

Answer 2

在SELECT关键字之后，您有?而不是*。

Answer 3

我想你想把assigned_pref_name作为一个字符串传递而不是变量名，所以：

   Cursor c = db.rawQuery(
              "SELECT ? FROM ? WHERE ? = ?",
                new String[]{
                PREF_STATUS,
                PREF_TABLE,
                PREF_NAME, 
                "assigned_pref_name" //as a string 
          });