2023年8月3日发(作者：)
mysql批量修改不同值_mysql批量更新多条记录的同⼀个字段为不同值的⽅法⾸先mysql更新数据的某个字段，⼀般这样写：UPDATE mytable SET myfield = 'value' WHERE other_field = 'other_value';也可以这样⽤in指定要更新的记录：UPDATE mytable SET myfield = 'value' WHERE other_field in ('other_values');这⾥注意 ‘other_values' 是⼀个逗号(，)分隔的字符串，如：1,2,3如果更新多条数据⽽且每条记录要更新的值不同，可能很多⼈会这样写：foreach ($values as $id => $myvalue) {$sql = "UPDATE mytable SET myfield = $myvalue WHERE id = $id";mysql_query($sql);}即是循环⼀条⼀条的更新记录。⼀条记录update⼀次，这样性能很差，也很容易造成阻塞。那么能不能⼀条sql语句实现批量更新呢？mysql并没有提供直接的⽅法来实现批量更新，但是可以⽤点⼩技巧来实现。UPDATE mytableSET myfield = CASE idWHEN 1 THEN 'myvalue1'WHEN 2 THEN 'myvalue2'WHEN 3 THEN 'myvalue3'ENDWHERE other_field ('other_values')如果where条件查询出记录的id不在CASE范围内，myfield将被设置为空。如果更新多个值的话，只需要稍加修改：UPDATE mytableSET myfield1 = CASE idWHEN 1 THEN 'myvalue11'WHEN 2 THEN 'myvalue12'WHEN 3 THEN 'myvalue13'END,myfield2 = CASE idWHEN 1 THEN 'myvalue21'WHEN 2 THEN 'myvalue22'WHEN 3 THEN 'myvalue23'ENDWHERE id IN (1,2,3)这⾥以php为例，构造这两条mysql语句：1、更新多条单个字段为不同值, mysql模式$ids_values = array(1 => 11,2 => 22,3 => 33,4 => 44,5 => 55,6 => 66,7 => 77,8 => 88,);$ids = implode(',', array_keys($ids_values ));$sql = "UPDATE mytable SET myfield = CASE id ";foreach ($ids_values as $id=> $myvalue) {$sql .= sprintf("WHEN %d THEN %d ", $id, $myvalue);}$sql .= "END WHERE id IN ($ids)";echo $sql.";";输出：UPDATE mytable SET myfield = CASE id WHEN 1 THEN 11 WHEN 2 THEN 22 WHEN 3 THEN 33 WHEN 4 THEN 44 WHEN5 THEN 55 WHEN 6 THEN 66 WHEN 7 THEN 77 WHEN 8 THEN 88 END WHERE id IN (1,2,3,4,5,6,7,8);2、更新多个字段为不同值, PDO模式$data = array(array('id' => 1, 'myfield1val' => 11, 'myfield2val' => 111), array('id' => 2, 'myfield1val' => 22, 'myfield2val' =>222));$where_in_ids = implode(',', array_map(function($v) {return ":id_" . $v['id'];}, $data));$update_sql = 'UPDATE mytable SET';$params = array();$update_sql .= ' myfield1 = CASE id';foreach($data as $key => $item) {$update_sql .= " WHEN :id_" . $key . " THEN :myfield1val_" . $key . " ";$params[":id_" . $key] = $item['id'];$params[":myfield1val_" . $key] = $item['myfield1val'];}$update_sql .= " END";$update_sql .= ',myfield2 = CASE id';foreach($data as $key => $item) {$update_sql .= " WHEN :id_" . $key . " THEN :myfield2val_" . $key . " ";$params[":id_" . $key] = $item['id'];$params[":myfield1va2_" . $key] = $item['myfield2val'];}$update_sql .= " END";$update_sql .= " WHERE id IN (" . $where_in_ids . ")";echo $update_sql.";";var_dump($params);输出：UPDATE mytable SET myfield1 = CASE id WHEN :id_0 THEN :myfield1val_0 WHEN :id_1 THEN :myfield1val_1 END,myfield2= CASE id WHEN :id_0 THEN :myfield2val_0 WHEN :id_1 THEN :myfield2val_1 END WHERE id IN (:id_1,:id_2);array (size=6)':id_0' => int 1':myfield1val_0' => int 11':id_1' => int 2':myfield1val_1' => int 22':myfield1va2_0' => int 111':myfield1va2_1' => int 222另外三种批量更新⽅式1. replace into 批量更新replace into mytable(id, myfield) values (1,'value1'),(2,'value2'),(3,'value3');2. insert into ...on duplicate key update批量更新insert into mytable(id, myfield1, myfield2) values (1,'value11','value21'),(2,'value12','value22'),(3,'value13','value23') onduplicate key update myfield1=values(myfield2),values(myfield2)+values(id);3. 临时表DROP TABLE IF EXISTS `tmptable`;create temporary table tmptable(id int(4) primary key,myfield varchar(50));insert into tmptable values (1,'value1'),(2,'value2'),(3,'value3');update mytable, tmptable set d = d where = ;【replace into】和【insert into】更新都依赖于主键或唯⼀值，并都可能造成新增记录的操作的结构隐患【replace into】操作本质是对重复记录先delete然后insert，如果更新的字段不全缺失的字段将被设置成缺省值【insert into】则只是update重复的记录，更改的字段只能依循公式值【临时表】⽅式需要⽤户有temporary 表的create 权限数量较少时【replace into】和【insert into】性能最好，数量⼤时【临时表】最好，【CASE】则具有通⽤型也不具结构隐患总结以上就是这篇⽂章的全部内容了，希望本⽂的内容对⼤家的学习或者⼯作能带来⼀定的帮助，如果有疑问⼤家可以留⾔交流。
2023年8月3日发(作者：)
mysql批量修改不同值_mysql批量更新多条记录的同⼀个字段为不同值的⽅法⾸先mysql更新数据的某个字段，⼀般这样写：UPDATE mytable SET myfield = 'value' WHERE other_field = 'other_value';也可以这样⽤in指定要更新的记录：UPDATE mytable SET myfield = 'value' WHERE other_field in ('other_values');这⾥注意 ‘other_values' 是⼀个逗号(，)分隔的字符串，如：1,2,3如果更新多条数据⽽且每条记录要更新的值不同，可能很多⼈会这样写：foreach ($values as $id => $myvalue) {$sql = "UPDATE mytable SET myfield = $myvalue WHERE id = $id";mysql_query($sql);}即是循环⼀条⼀条的更新记录。⼀条记录update⼀次，这样性能很差，也很容易造成阻塞。那么能不能⼀条sql语句实现批量更新呢？mysql并没有提供直接的⽅法来实现批量更新，但是可以⽤点⼩技巧来实现。UPDATE mytableSET myfield = CASE idWHEN 1 THEN 'myvalue1'WHEN 2 THEN 'myvalue2'WHEN 3 THEN 'myvalue3'ENDWHERE other_field ('other_values')如果where条件查询出记录的id不在CASE范围内，myfield将被设置为空。如果更新多个值的话，只需要稍加修改：UPDATE mytableSET myfield1 = CASE idWHEN 1 THEN 'myvalue11'WHEN 2 THEN 'myvalue12'WHEN 3 THEN 'myvalue13'END,myfield2 = CASE idWHEN 1 THEN 'myvalue21'WHEN 2 THEN 'myvalue22'WHEN 3 THEN 'myvalue23'ENDWHERE id IN (1,2,3)这⾥以php为例，构造这两条mysql语句：1、更新多条单个字段为不同值, mysql模式$ids_values = array(1 => 11,2 => 22,3 => 33,4 => 44,5 => 55,6 => 66,7 => 77,8 => 88,);$ids = implode(',', array_keys($ids_values ));$sql = "UPDATE mytable SET myfield = CASE id ";foreach ($ids_values as $id=> $myvalue) {$sql .= sprintf("WHEN %d THEN %d ", $id, $myvalue);}$sql .= "END WHERE id IN ($ids)";echo $sql.";";输出：UPDATE mytable SET myfield = CASE id WHEN 1 THEN 11 WHEN 2 THEN 22 WHEN 3 THEN 33 WHEN 4 THEN 44 WHEN5 THEN 55 WHEN 6 THEN 66 WHEN 7 THEN 77 WHEN 8 THEN 88 END WHERE id IN (1,2,3,4,5,6,7,8);2、更新多个字段为不同值, PDO模式$data = array(array('id' => 1, 'myfield1val' => 11, 'myfield2val' => 111), array('id' => 2, 'myfield1val' => 22, 'myfield2val' =>222));$where_in_ids = implode(',', array_map(function($v) {return ":id_" . $v['id'];}, $data));$update_sql = 'UPDATE mytable SET';$params = array();$update_sql .= ' myfield1 = CASE id';foreach($data as $key => $item) {$update_sql .= " WHEN :id_" . $key . " THEN :myfield1val_" . $key . " ";$params[":id_" . $key] = $item['id'];$params[":myfield1val_" . $key] = $item['myfield1val'];}$update_sql .= " END";$update_sql .= ',myfield2 = CASE id';foreach($data as $key => $item) {$update_sql .= " WHEN :id_" . $key . " THEN :myfield2val_" . $key . " ";$params[":id_" . $key] = $item['id'];$params[":myfield1va2_" . $key] = $item['myfield2val'];}$update_sql .= " END";$update_sql .= " WHERE id IN (" . $where_in_ids . ")";echo $update_sql.";";var_dump($params);输出：UPDATE mytable SET myfield1 = CASE id WHEN :id_0 THEN :myfield1val_0 WHEN :id_1 THEN :myfield1val_1 END,myfield2= CASE id WHEN :id_0 THEN :myfield2val_0 WHEN :id_1 THEN :myfield2val_1 END WHERE id IN (:id_1,:id_2);array (size=6)':id_0' => int 1':myfield1val_0' => int 11':id_1' => int 2':myfield1val_1' => int 22':myfield1va2_0' => int 111':myfield1va2_1' => int 222另外三种批量更新⽅式1. replace into 批量更新replace into mytable(id, myfield) values (1,'value1'),(2,'value2'),(3,'value3');2. insert into ...on duplicate key update批量更新insert into mytable(id, myfield1, myfield2) values (1,'value11','value21'),(2,'value12','value22'),(3,'value13','value23') onduplicate key update myfield1=values(myfield2),values(myfield2)+values(id);3. 临时表DROP TABLE IF EXISTS `tmptable`;create temporary table tmptable(id int(4) primary key,myfield varchar(50));insert into tmptable values (1,'value1'),(2,'value2'),(3,'value3');update mytable, tmptable set d = d where = ;【replace into】和【insert into】更新都依赖于主键或唯⼀值，并都可能造成新增记录的操作的结构隐患【replace into】操作本质是对重复记录先delete然后insert，如果更新的字段不全缺失的字段将被设置成缺省值【insert into】则只是update重复的记录，更改的字段只能依循公式值【临时表】⽅式需要⽤户有temporary 表的create 权限数量较少时【replace into】和【insert into】性能最好，数量⼤时【临时表】最好，【CASE】则具有通⽤型也不具结构隐患总结以上就是这篇⽂章的全部内容了，希望本⽂的内容对⼤家的学习或者⼯作能带来⼀定的帮助，如果有疑问⼤家可以留⾔交流。
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