duplicate annihilator

MySQL query repeating fields, and how to delete duplicate recordsMySQL, database, Database, field, serverThere is a large table in the database and you need to look for a duplicate record ID for the name in order to compare it. If you are simply looking for a word that is not duplicated in the database , it is easy to:SELECT min (' id '), ' name ' from ' table ' GROUP by ' name ';However, this does not gi

For example:ID Name Value1 a pp2 a PP3 B III4 B pp5 B pp6 C pp7 C pp8 C IIIID is primary keyAsk for such a resultID Name Value1 a pp3 B III4 B pp6 C pp8 C IIIMethod 1Delete yourtablewhere [id] not in (Select MAX ([id]) from yourtableGroup BY (name + value))Method 2Delete aFrom Table a LEFT join (Select Id=min (ID) from table GROUP by Name,value) B on A.id=b.idwhere b.id is nullSQL statement for querying and deleting duplicate recordsSQL statement for

Searching and deleting duplicate rows in the database Search for records with all repeated titles:Select *From t_infoWhere (select count (*)From t_infoWhere title = A. Title)> 1)Order by title DESCI. Searching duplicate records1. Search for all Repeated RecordsSelect * from table where repeated field in (select repeated field from Table group by repeated field having count (*)> 1)2. Filter

How does MySQL solve the unique primary key duplicate value during the insertion process? mysql primary key This article describes how to avoid DUPLICATE keys when inserting data into a table. It mainly involves IGNORE, on duplicate key update, and REPLACE; next, let's take a look at the three solutions. IGNORE Ignore is used to automatically ignore

We may have this situation, a table originally poorly designed, resulting in the table data data duplication, then, how to delete the duplicate data.Duplicate data may have two scenarios, the first one being only some of the fields in the table, and the second is exactly the same as two rows of records.One, for partial field duplicate data deletionLet's talk about how to query for

MySQL database, often encounter duplicate records, then need to delete duplicate records SQL, the following list of four ways to delete duplicate records, for different situations, I hope to help you. 1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to judge

A1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determineSELECT * from Peoplewhere Peopleid in (select Peopleid from People GROUP by Peopleid have count (Peopleid) > 1)Example two:SELECT * FROM TestTablewhere Numeber in (select number from people group by number has count (number) > 1)You can find the same number of records in the TestTable table.2, delete redundant records in the table,

In-depth analysis of mysql "on duplicate key update" syntax, mysqlduplicate Mysql "on duplicate key update" SyntaxIf the on duplicate key update is specified at the end of the INSERT statement and the DUPLICATE value appears in a UNIQUE index or primary key after the row is inserted, UPDATE is executed ON the row with

Redundancy and duplicate index redundancy and duplicate index concept: MySQL allows you to create multiple indexes on the same column, whether there is .. Redundancy and duplicate index redundancy and duplicate index concept: MySQL allows you to create multiple indexes on the same column, whether there is .. Redunda

of the code is to delete the duplicate records in the Tbtradefullinfoget and save only the largest Intime record in the table! Some other delete duplicate records SQL statements 1, SQL Server lookup table redundant duplicate record, duplicate record is based on a single field (Peopleid) to judge The cod

How does MySQL process the unique primary key duplicate value during the insertion process? mysql primary keyIntroduction This article describes how to avoid DUPLICATE keys when inserting data into a table. It mainly involves IGNORE, on duplicate key update, and REPLACE; next, let's take a look at the three solutions. IGNORE Ignore is used to automatically ignor

For example, now there is a person table (table name: peosons)If you want to have the name, ID number, address of these three fields exactly the same records query Copy Code code as follows: Select p1.* From persons p1,persons P2 where p1.idand P1.cardid = P2.cardid and P1.pname = p2.pname and p1.address = p2.address can achieve this effect. Several SQL statements that delete duplicate records 1. Using the rowID method 2. U

Now many people like to use the network disk to store some important files, or to share the files of others into their own network disk. But a long time will inevitably appear, some different names but the same content of the file, which will occupy too much disk space. So how do you quickly parse these duplicate files and remove them from the disk space? 　　1. Self-function Quick Scan Because many netizens have similar demand, so some network disk o

Tags: log span _id Select TMP judgment method generated SQL statements:1.Select COUNT (Distinct ann_id) fromDmdb.t_bond_ann_att_info where Last_update_time >='2018-03-09 14:00:00'; 2.Select COUNT (ID) fromDmdb.t_bond_ann_info where Create_time >='2018-03-09 14:00:00'; 3.Select a.* fromDmdb.t_bond_ann_info a where a.id not inch(select ann_id fromT_bond_ann_att_info where Last_update_time>='2018-03-09 14:00:00' ) andA.create_time >='2018-03-09 14:00:00'; 4.Select distinct a.ann_id fromDmdb.t_b

Find records for all duplicate headings: SELECT * from T_info a WHERE (SELECT COUNT (*) from t_info where title = A.title) > 1) Order by Title DESC First, find duplicate records 1. Find all duplicate records SELECT * FROM table Where repeat field in (Select repeating field from table Group by repeating field having Count (*) >1) 2. Filter