Snowflake not recognizing data type in ADD column

Question

A little new to SQL. Created a new table from a copy in another database and am trying to add columns and update them so I can merge three tables into one.

For some reason when I try to add columns snowflake isn't recognizing my data type.

the code is something like:

ALTER TABLE CUSTOMERS
ADD COLUMNS
   FIRSTNAME varchar(99999),
   LASTNAME varchar(99999),
   DATE timestamp_ntz(00:00:00.000);

But I keep receiving errors saying unexpected 'varchar'. I am not sure what I am missing here, but I need the data types to match my other table so I can update it.

Answer 1

Correct syntax should use COLUMN or skip it at all, timestamp_ntz(00:00:00.000); is also incorrect as parameter should be integer indicating precision:

CREATE OR REPLACE TABLE CUSTOMERS(i INT);

ALTER TABLE CUSTOMERS
ADD 
   FIRSTNAME varchar(99999),
   LASTNAME varchar(99999),
   DATE timestamp_ntz(3);

ALTER TABLE CUSTOMERS
ADD COLUMN                      -- instead of COLUMNS
   FIRSTNAME varchar(99999),
   LASTNAME varchar(99999),
   DATE timestamp_ntz(3);

SELECT * FROM CUSTOMERS;

Output: