delete duplicate rows in sql

Solution 1:Add Unique Index on your table:ALTER IGNORE TABLE `TableA` ADD UNIQUE INDEX (`member_id`, `quiz_num`, `question_num`, `answer_num`);Solution 2:ADD Primry key in your table and can easily remove duplicates from your table using below query:DELETE FROM member WHERE id IN (SELECT * FROM (SELECT id FROM member GROUP BY member_id, quiz_num, question_num, answer_num HAVING (COUNT(*) > 1) ) AS A );Solution 3:SELECT DISTINCT * INT

Oracle deletes duplicate data with only one SQL statement www.2cto.com for querying and deleting duplicate records 1. Searches for redundant duplicate records in the Table. duplicate records are based on a single field (Id) select * from table where Id in (select Id from Tab

The multi-row delete operation of listView is deleted from the database.Private void buttonDelete_Click (object sender, EventArgs e){DialogResult dr = MessageBox. Show ("are you sure you want to delete the selected record? "," Photonsoft ", MessageBoxButtons. OKCancel, MessageBoxIcon. Question );If (dr = DialogResult. OK){Try{Dbcon. OpenConn (); // open the Oracle connection.String id = ""; // The id here i

SQL statements used to query and delete duplicate records in Oracle 1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (Id ). Select * from table where Id in (select Id from Table group byId having count (Id)> 1)

Data acquisition, due to the early analysis of the structure of the page is not perfect, resulting in a part of the data collected. After perfecting the code, rerun the scrapy, collect some duplicate data, and search the method of deleting duplicate data.n.b. When you delete duplicate data from a data table, back up th

Data | repeat | Duplicate record delete a traffic violation data table duplicate record (same time [haptime], vehicle number number [numberplate], the punishment reason [reason]) First, the principle of the method: 1. In Oracle, each record has a rowid,rowid that is unique across the database, ROWID determines which data files, blocks, and

Oracle databases contain many duplicate items because they do not have any constraints. The question now is how to delete these repeated items. Repeat records only keep one of them. The following table creation statement: CREATETABLEmessage_s Oracle databases contain many duplicate items because they do not have any constraints. The question now is how to

Example of table structure for deleting duplicate data in a data table: [SQL] MyTable ----------- primary (2048) primarykey, Col1varchar (20) notnull, Col2varchar () notnull, Col3tinyintnotnull solution: [SQL] Explain Example of table structure for deleting duplicate data in a data table: [

MiniD from student group by name;Query OK, 3 rows affectedRecords:3 duplicates:0 warnings:0mysql> Delete from student where ID not in (select MiniD from temp);Query OK, 3 rows affectedMysql> select * from student;+----+------+| ID | NAME |+----+------+| 11 | AA || 13 | bb || 16 | CC |+----+------+3 Rows in SetMethod 3

) as MiniD from student group by name;Query OK, 3 rows affectedRecords:3 duplicates:0 warnings:0mysql> Delete from student where ID not in (select MiniD from temp);Query OK, 3 rows affectedMysql> select * from student;+----+------+| ID | NAME |+----+------+| 11 | AA || 13 | bb || 16 | CC |+----+------+3 Rows in Set

1. Let's test it for you first. Open the wps table and click "data = repeated items = highlighted repeated items = set" as shown in the following figure"2. As shown in the following figure, duplicate data is displayed, for example, the content of the ninth and tenth rows is the same as that of the sixth and eighth rows.Why do I delete repeated

In thousands of records, there are some of the same records, how can you use SQL statements, delete duplicates? Thank you!1, find redundant records in the table, duplicate records are judged by a single field (Peopleid) select* frompeoplewherepeopleidin (selectpeopleidfrom Peoplegroupbypeopleidhavingcount (peopleId) >1) 2, d