How to access the value of an array within a while loop in SQL?

Question

In the database I’m working on there are a number of salary variables that are registered as strings with entries like 0000001155,00. I’m using a combination of CAST and REPLACE to turn these variables into float. For only one variable, I used:

CAST(REPLACE(vl_salario_contratual, ",", ".") AS float64) as wage_formatted

It turns out that I would like to perform this procedure for all the variables that present the same problem. I read in this question that doesn’t exist FOR LOOP in SQL, so I tried to use the WHILE LOOP, indicated in the answers, along with an array with the names of the variables I intend to change. Additionally, I read the documentation Big Query to adapt response code to BQ syntax.

Follows my code:

DECLARE
  cnt INT64;
DECLARE
  wage_vars ARRAY<STRING>;
SET
  cnt=1;
SET
  wage_vars=( vl_salario_contratual,
    vl_remun_media_nom );
WHILE
  @cnt < 3 DO CAST(REPLACE(@wage_vars[@cnt], ",", ".") AS float64) #erro ocorre aqui
SET
  @cnt = @cnt + 1;
END

The program indicates that the error occurs in @wage_vars[@cnt] and therefore this form of indexing is not accepted. I tried an alternative method after reading this question. Follows code:

DECLARE
  wage_vars ARRAY<STRING>;
SET
  wage_vars=( vl_salario_contratual,
    vl_remun_media_nom );
SELECT * FROM wage_vars WHERE id IN(1,2)
  CAST(REPLACE(wage_vars[id], ",", ".") AS float64)

Also unsuccessful.

How do I access elements from an array within a while loop in SQL?