Unable to fetch an sqlite record

I am using the following query to fetch a row with a particular mid.

Cursor mCursor =  mDb.query(true, DATABASE_TABLE, new String[] { KEY_ROWID, "actionData", "mid" }, "mid" + "=" + mid, null, null, null, null, null);

I however get an 开发者_运维知识库sqlite exception when I try to do the same. Any ideas?

The exception is -

 Error: android.database.sqlite.SQLiteException: no such column: qVEl3: , while compiling: SELECT DISTINCT _id, actionData, mid FROM notifs WHERE mid=qVEl3

You missed the quotations:

SELECT DISTINCT _id, actionData, mid FROM notifs WHERE mid='qVEl3'

So your Android code should be :

Cursor mCursor =  mDb.query(true, DATABASE_TABLE, new String[] 
    { KEY_ROWID, "actionData", "mid" }, 
    "mid=?", new String[] {mid}, null, null, null, null);

(that will prevent SQL injection too)

You'll want to use query parameters to avoid issues with quotes:

Cursor mCursor =  mDb.query(
    true,
    DATABASE_TABLE,
    new String[] { KEY_ROWID, "actionData", "mid" }, 
    "mid = ?",              // the ? is a placeholder.
    new String[] { mid },   // sqlite will put the value of mid into the placeholder above.
    null,
    null,
    null,
    null);