I get the following error when executing an sql query and can’t figure out what I’m doing wrong, please help me. The purpose of the query is to calculate the median cost of orders for all tables – even

Text error:
“No operator matches the given name and argument types. You might need to add explicit type casts.”

columns:
rn – result function row_number
price – values price

sql text:

SELECT CASE 
    WHEN (SELECT MAX(rn) FROM even) % 2 = 0 
        THEN (
            (SELECT price FROM even WHERE rn = (SELECT MAX(rn) FROM even)::decimal // 2)
            +
            (SELECT price FROM even WHERE rn = (SELECT MAX(rn) FROM even)::decimal // 2 + 1)
        ) / 2
    ELSE 
        (SELECT price FROM even WHERE rn = (SELECT MAX(rn) FROM even)::decimal // 2 + 1) 
END AS median_price
FROM even

I tried changing all the data types.