Question

so in my database some rows have NULL values, and when I select * from table, that NULL values also shows as text “null”. So I want to hide all NULL values. Does anyone have idea for query? Thanks!

this is my input in DB:

db.execSQL("CREATE TABLE IF NOT EXISTS table (name VARCHAR, kg VARCHAR,   pod                 VARCHAR,reps VARCHAR, time VARCHAR );");
  db.execSQL("INSERT INTO table VALUES('name 1',NULL,NULL , NULL , '"+s+"');");
 db.execSQL("INSERT INTO table VALUES(NULL,'S 1','"+ee5+"' , '"+ee+"' , '"+s+"');");
 db.execSQL("INSERT INTO table VALUES(NULL,'S 2','"+ee6+"' , '"+ee2+"', '"+s+"');");
 db.execSQL("INSERT INTO table VALUES(NULL,'S 3','"+ee7+"' , '"+ee3+"', '"+s+"');");
 db.execSQL("INSERT INTO table VALUES(NULL,'S 4','"+ee8+"' , '"+ee4+"', '"+s+"');");

Answer 1

This is what you are looking for:

SELECT x, y, etc, CASE WHEN field IS NOT NULL THEN field ELSE '' END AS hehe FROM table;

Edit: Addin to your comments, this is pretty trivial once you know how to do it for one column. Apply the same for all columns. In SO dont expect homeworks to get done, instead expect a help to solve your problem which ultimately you yourself have to do.

Btw, here is how..

SELECT COALESCE(name, ''), COALESCE(kg, ''), COALESCE(pod, ''), COALESCE(reps, ''), 
       COALESCE(time, '') 
FROM   table

You have three good methods in this thread (including mine), and I personally feel the other two are more intuitive. Use any by applying the same logic as I have shown.