這篇文章主要介紹了mysqlmysql重復的數據 mysql數據去重復,需要的朋友可以參考下
select?*?from?employee?group?by?emp_name?having?count?(*)>1;
mysql? 查詢可以刪除的重復數據
select?t1.*?from?employee?t1?where?(t1.emp_name)?in?(select?t4.emp_name?from?(select?t2.emp_name?from?employee?t2?group?by?t2.emp_name?having?count(*)>1)?t4)?and?t1.emp_id?not?in?(select?t5.emp_id?from?(select?min(t3.emp_id)?as?emp_id?from?employee?t3?group?by?t3.emp_name?having?count(*)>1)?t5);
Mysql? 刪除重復的數據
delete?t1?from?employee?t1?where?(t1.emp_name)?in?(select?t4.emp_name?from?(select?t2.emp_name?from?employee?t2?group?by?t2.emp_name?having?count(*)>1)?t4)?and?t1.emp_id?not?in?(select?t5.emp_id?from?(select?min(t3.emp_id)?as?emp_id?from?employee?t3?group?by?t3.emp_name?having?count(*)>1)?t5);
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