SQL query is not working when I am using Equals query

Database :

if (DatabaseUtils.queryNumEntries(foodDBHlpr.getWritableDatabase(),FoodDatabaseHelper.TABLE_NAME ) < 1) {

            foodDBHlpr.insertFood("John", "Mashed potato");
            foodDBHlpr.insertFood("Johnson", "Pineapple pie");
           
}

SQL query

public Cursor getFoodsWithProvidedFood(String provided_food) {
        return this.getWritableDatabase().query(
                TABLE_NAME,
                null,
                COL_2 + " LIKE '%"  +provided_food.replace("'",  "''") + "%' ",
                null,
                null,
                null,
                null
        );

mCsr = foodDBHlpr.getFoodsWithProvidedFood(alfabetsearch);
      
        while (mCsr.moveToNext()) {
          PreferredFood=mCsr.getString(mCsr.getColumnIndex(FoodDatabaseHelper.COL_3));

        }

When I use "Like " query everything is working fine, however when I look for John, it shows both results for John as Johnson as they are similar. But when I search John it must only show the result for John ( not Johnson).

So far I tried :

1. COL_2 + "="+""  +provided_food.replace("'",  "''")+",
 1. COL_2 + "="  +provided_food.replace("'",  "''") + " ",

But it is not working LogCat :

E/SQLiteLog: (1) no such column: John in "SELECT * FROM dataset WHERE Food=John"

    --------- beginning of crash
2022-03-27 18:44:09.867 7571-7639/com.example.humanuz E/AndroidRuntime: FATAL EXCEPTION: Thread-3
    Process: com.example.humanuz, PID: 7571
    android.database.sqlite.SQLiteException: no such column: John (code 1 SQLITE_ERROR): , while compiling: SELECT * FROM dataset WHERE Food=John
        at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
        at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1045)
        at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:652)
        at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:590)
        at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:61)
        at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
        at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:46)
        at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1545)
        at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1392)
        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1263)
        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1431)
        at com.example.humanuz.FoodDatabaseHelper.getFoodsWithProvidedFood(FoodDatabaseHelper.java:60)
        at com.example.humanuz.MainActivity.Search(MainActivity.java:3805)

Please give me a hint.

Solution

This is becuase of how SQL process your Query. In your when clause, SQL is referring John as a table column instead of String. As a result, SQL is trying to find John as a table column and failing. This can be fixed by simply adding quotes around the value in your codebase as follow:

COL_2 + "'"  +provided_food.replace("'",  "''") + "'"

COL_2 + "\""  +provided_food.replace("'",  "''") + "\""

The Like query only worked because you were placing the '(single quote) around the value. Similarly, once you put some quote (single or double) around the value, it would work.