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javaandroidsqlandroid-contentprovider

How to query a ContentProvider for value that is not null on Android?

I have a ContentProvider, and I would like to make a query that returns the rows of a table where the values of a specific column is not null. In SQL you can use the column IS NOT NULL, but I cannot figure out what is the equivalent statement in case of ContentProviders.

I have tried so far:

  1. SQL like syntax.

    getContentProvider().query(uri,
        null,
        Contract.Table.COLUMN + " is not null",
        null,
        null);

  2. SQL like syntax with selection arguments.

    getContentProvider().query(uri,
        null,
        Contract.Table.COLUMN + " is not null",
        new String[0],
        null);

  3. Is on equal with real null value.

    getContentProvider().query(uri,
        null,
        Contract.Table.COLUMN + " != ?",
        new String[]{null},
        null);

  4. Is not equal with "null" string.

    getContentProvider().query(uri,
        null,
        Contract.Table.COLUMN + " != ?",
        new String[]{"null"},
        null);

Thank you!

Solution

  • ContentProviders are not standardized. Each of them may interpret query parameters in any given way. (In fact, most content providers only use a few parameters at all.)