left join聯合的時候去重

SELECT * from t_ss; SELECT * from t_kk; SELECT * from t_ss s LEFT JOIN t_kk k on s.id=k.sid 使用group by去重 SELECT * from t_ss s LEFT JOIN t_kk k on s.id=k.sid GROUP BY k.sid; 或者 SELECT * from t_ss s LEF

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