I have 2 columns of type int and I want to make a concat to two columns in presto syntax. it is possible? for example:

id:

1. 345
2. 997

age:

1. 23
2. 55

new_col:

1. 34523

2. 99755

I was trying to use the array function but it is not working :/

thanks to everyone!

CodePudding user response：

As presto can not convert automatically

CONCAT(cast(id as varchar),cast(age as varchar))

CodePudding user response：

You concatenate strings.

You calculate with integers.

So, multiply one column by 100, and add the other. And the result is another integer, not a string.

Data Types matter. And integers are way faster than strings.

WITH
-- your input, one table, don't use in final query ...
id(id,idcol) AS (
            SELECT 1, 345
  UNION ALL SELECT 2, 997
)
,
-- your input, other table, don't use in final query ...
age(id,agecol) AS (
            SELECT 1, 23
  UNION ALL SELECT 2, 55
)
-- real query starts here ...
SELECT
  id.id
, idcol * 100   agecol AS new_col
FROM id JOIN age USING(id)
ORDER BY 1
-- out  id | new_col 
-- out ---- ---------
-- out   1 |   34523
-- out   2 |   99755