-- 這種場(chǎng)景下得到的是t_name和t_age的交集數(shù)據(jù)
    SELECT n.*,a.* from t_name n,t_age a where n.id = a.id;
    
    SELECT n.*,a.* from t_name n INNER JOIN t_age a on n.id = a.id;
    
    SELECT n.*,a.* from t_name n JOIN t_age a on n.id = a.id;
    
    -- 這種場(chǎng)景下得到的是t_name的所有數(shù)據(jù)，和滿足某一條件的t_age的數(shù)據(jù)
    SELECT n.*,a.* from t_name n LEFT JOIN t_age a on n.id = a.id;
    
    SELECT n.*,a.* from t_name n LEFT outer JOIN t_age a on n.id = a.id;
    
    -- t_name中的所有數(shù)據(jù)減去"與t_age滿足同一條件 的數(shù)據(jù)"，然后得到的t_name剩余數(shù)據(jù)
    SELECT n.*,a.* from t_name n LEFT JOIN t_age a on n.id = a.id where a.id is null;
    
    -- 這種場(chǎng)景下得到的是t_age的所有數(shù)據(jù)，和滿足某一條件的t_name的數(shù)據(jù)
    SELECT n.*,a.* from t_name n right JOIN t_age a on n.id = a.id;
    
    -- t_name中的所有數(shù)據(jù)減去"與t_age滿足同一條件 的數(shù)據(jù)"，然后得到的t_name剩余數(shù)據(jù)
    SELECT n.*,a.* from t_name n right JOIN t_age a on n.id = a.id where n.id is null;
    
    -- union過(guò)后，重復(fù)的記錄會(huì)合并，所以結(jié)果如下
    SELECT n.*,a.* from t_name n LEFT JOIN t_age a on n.id = a.id
    UNION
    SELECT n.*,a.* from t_name n right JOIN t_age a on n.id = a.id;
    
    -- t_name中的所有數(shù)據(jù)減去"與t_age滿足同一條件 的數(shù)據(jù)"，然后得到的t_name剩余數(shù)據(jù)
    (SELECT n.*,a.* from t_name n LEFT JOIN t_age a on n.id = a.id where a.id is null)
    UNION
    (SELECT n.*,a.* from t_name n right JOIN t_age a on n.id = a.id where n.id is null);
    ```