How do I update a column with a NULL value in Teradata?

Question

I have got a table which has thousands of rows and hundreds of columns. I need to insert NULL value in all the columns except THREE for FIRST 15 rows. How do I approach with this problem statement?

I will provide with a small example below. Ex.

ID   FirstNM    MiddleNM    LastNM    Gender    

1    John       H           Doe       M
2    Katie      F           Hopkins   F
3    Michelle   A           Slater    M
4    John       B           Kiwi      M
5    Alexander  C           Slander   M
6    Arda       D           Putin     M
7    Anuj       R           Trump     M
8    Priyanka   E           Moss      M
9    Hashim     F           George    M
10   Donald     G           Junior    M
11   Valdimir   W           Senior    M
12   Phoenix    Q           Cherkov   M

My output should look something like this.

ID   FirstNM    MiddleNM    LastNM    Gender    

1    NULL       NULL        NULL      NULL
2    NULL       NULL        NULL      NULL
3    NULL       NULL        NULL      NULL
4    NULL       NULL        NULL      NULL
5    NULL       NULL        NULL      NULL
6    Arda       D           Putin     M
7    Anuj       R           Trump     M
8    Priyanka   E           Moss      M
9    Hashim     F           George    M
10   Donald     G           Junior    M
11   Valdimir   W           Senior    M
12   Phoenix    Q           Cherkov   M

Answer 1

You can simply use the below update command -

UPDATE T
SET GENDER = NULL
   -- ,List all other columns assigning null value
WHERE ID <= 15;

Hope this helps.