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Android sqlite – select records where field is null or empty

Posted by: admin April 23, 2020 Leave a comment

Questions:

My application has an sqlite DB, where some of the fields are null or empty (meaning that I never inserted anything into that field).

I wish to select all the records for which the field is null or empty.

This is what I have tried:

cursor = db.query(DBHelper.TABLE_NAME, COLUMNS, "folder_name = ? ", new String[] {"null"}, null, null, DBHelper.TIMESTAMP_COL + " DESC");

But that didn’t work, and I didn’t get any records. What do I need to do to make this work?

How to&Answers:

Try

cursor = db.query(DBHelper.TABLE_NAME, COLUMNS, "folder_name is null or folder_name = ?", new String[] {""}, null, null, DBHelper.TIMESTAMP_COL + " DESC");

Answer:

db.rawQuery("SELECT * FROM myTable WHERE myColumn IS NULL", null);

Answer:

Just use “folder_name is null”

Answer:

I am using android studio 3.4,
Room 2.1.0-alpha07

This is my Kotlin Code
I tried using this didn’t work as expected

`@Query("SELECT *FROM notifications WHERE status=:status OR status = null")`   

This one is working fine

@Query("SELECT *FROM notifications WHERE status=:status OR status is null")