WITH SUR_19 AS(
    SELECT
        GENDER_CODE,
        AGE,
        CASE WHEN CATEGORY_CODE='10' THEN AVERAGE_VALUE ELSE NULL END AS HEIGHT,
        CASE WHEN CATEGORY_CODE='20' THEN AVERAGE_VALUE ELSE NULL END AS WEIGHT
    FROM
        SCHOOL_HEALTH
    WHERE
        SURVEY_YEAR=2019
)

SELECT
    CASE WHEN GENDER_CODE='20' THEN 'MALE'
        WHEN GENDER_CODE='30' THEN 'FEMALE'
    END AS GENDER,
    AGE,
    ROUND(AVG(HEIGHT),1) AS H_AVG,
    ROUND(AVG(WEIGHT),1) AS W_AVG
FROM
    SUR_19
GROUP BY
    GENDER_CODE,
    AGE;