SELECT
    ITEM_CODE AS ITEM
    , ITEM_NAME AS I_NAME
    , CL_NAME AS C_NAME
    , SIZE_NAME AS S_NAME 
FROM
    ITEM 
    -- 交差結合で全てのテーブルを結合
    JOIN COLOR_TBL 
    JOIN SIZE_TBL 
WHERE
    -- 在庫管理する商品のみ対象
    STOCK_MANAGEMENT_TYPE = 1 
ORDER BY
    ITEM_CODE ASC
    , CL_CODE ASC
    , SIZE_CODE ASC;