-- 检查用户ID=1的头像数据
SELECT 
    id,
    nickname,
    avatar,
    CHAR_LENGTH(avatar) as avatar_length,
    LENGTH(avatar) as avatar_bytes,
    HEX(avatar) as avatar_hex
FROM user 
WHERE id = 1;

-- 检查最近上传的头像记录
SELECT 
    id,
    nickname,
    avatar,
    update_time
FROM user 
WHERE avatar IS NOT NULL 
  AND avatar != ''
ORDER BY update_time DESC 
LIMIT 5;