how to set value in other column while using case statement in SQL

Question

I creating different labels for my column, depending on various conditions. And it looks like this:

, CASE
    WHEN phone like '%555%' THEN 1
    ELSE 0
END AS first_label

, CASE
    WHEN phone like '%888%' THEN 1
    ELSE 0
END AS second_label

But also i need to name this new lable in new column like lable name = 'first_label' for each row. So how can i do it whithout copying that blocks again? My result:

SELECT 
, phone    
, CASE
    WHEN phone like '%555%' THEN 1
    ELSE 0
END AS first_label
, CASE
    WHEN phone like '%888%' THEN 1
    ELSE 0
END AS second_label
, 'lable_name' as lable_name

FROM mytable

expected output:

phone	first_label	second_label	lable_name
555 75 71 1	1	0	first_label
888 94 18 3	0	1	second_label

Answer 1

In order not to repeat the expressions again, simply select from your query result. E.g.:

WITH labeled AS
(
  SELECT 
    phone, 
    CASE WHEN phone like '%555%' THEN 1 ELSE 0 END AS first_label,
    CASE WHEN phone like '%888%' THEN 1 ELSE 0 END AS second_label
  FROM mytable
)
SELECT
  phone,
  first_label,
  second_label,
  CASE
    WHEN first_label = 1 AND second_label = 1 THEN 'both labels'
    WHEN first_label = 1 AND second_label = 0 THEN 'first_label'
    WHEN first_label = 0 AND second_label = 1 THEN 'second_label'
    ELSE                                           'no label'
  END AS label_names
FROM labeled;

Demo: https://dbfiddle.uk/zwDO1N1Q