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There are several identical records in thousands of records. How can I use SQL statements to delete duplicates? 1. Search for redundant duplicate records in the Table. duplicate
These are some useful SQL statements. For more information, see. These are some useful SQL statements. For more information, see. Delete duplicate records and save the non-Repeated Records in TABLE_NAME to # TABLE_NAME Select di
Delete duplicate records and save the non-Repeated Records in table_name to # table_name Select distinct * into # table_name from table_nameDelete from table_nameSelect * into table_name from # table_nameDrop table # table_name This is related to the "select into" option, which can be in the database attributeIn
redundant duplicate records in the table (multiple fields) The code is as follows:Copy code Select * from vitae a where (a. peopleId, a. seq) in (select peopleId, seq from vitae group by peopleId, seq having count (*)> 1) 4. Delete redundant record (multiple fields) in the table, leaving only the records with the
For example, the table test contains the ID and name fields. If there are records with the same name, only one record is left, and the remaining records are deleted. The content of the name is not fixed, and the number of identical records is not fixed. Solution 1: 1. Record Repeated Records in Table temp1: Selec
SQL statement for mysql to delete duplicate data and mysql to delete data Create table tmp as select id FROM get_review_url WHERE (no, title, name, content) IN (SELECT no, title, name, content FROM get_review_url group by no, title, name, content having count (*)> 1) AND id not in (select min (id) FROM get_review_url
about 4 hours. 4 hours, a long time. It takes less than 10 minutes to insert 5 million data deduplication (1/2 duplicates) to a temporary table.Remove duplicate records from SQL statements and obtain duplicate records Search for duplic
repetitions) in less than 10 minutes.In fact, with the deletion method is relatively slow, may be the edge to find the reason for the deletion, and the use of temporary table, you can not duplicate the data ID to be selected to put in the temporary table, and then the table information by the temporary tables of the selected ID, they find to insert into the new table, and then delete the original table, so
1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (peopleId ).Copy codeThe Code is as follows:Select * from peopleWhere peopleId in (select peopleId from people group by peopleId having count (PeopleId)> 1)2. Delete
table tmp_wrap;Query OK, 0 rows affected (0.05 sec) 2. There is also a very streamlined approach. Find the duplicate and remove the smallest one. The Code is as follows: Delete users_groups as a from users_groups as,(Select *, min (id) from users_groups group by uid having count (1)> 1) As BWhere a. uid = B. uid and a. id> B. id;(7 row (s) affected)(0 MS taken) Query result
duplicate records in the table, and judge based on a single field (peopleId).Select * from peopleWhere peopleId in (select peopleId from people group by peopleId having count(PeopleId)> 1)2. Delete redundant record in the table. The record is determined based on a single field (eagleid). Only the records with the smal
This article describes three SQL statements for querying duplicate records and deleting duplicate records. Each of them uses different methods to illustrate other functions, feasibility, and efficiency. This article describes three SQL
duplicate records)-- The premise of such a score is: there must be a non-repeated column, in this example, recno-- For example, query records with duplicate stuidSelect * From stuinfo S1Where recno not in (Select max (recno) from stuinfo S2Where s1.stuid = s2.stuid) The following figure shows all
When the SQL statement deletes duplicate records and there is no size relationship between them, it processes repeated values. When the SQL statement deletes duplicate records and there is no size relationship between them, it pro
During data development, we often need to identify duplicate records in the database or directly Delete duplicate records in the database. Below I will summarize some methods for you. If you need them, please refer to them. During data development, we often need to identify
Example:Table stuinfo, which has three fields: recno (auto-increment), stuid, and stuname The SQL statement used to create the table is as follows: Create Table [stuinfo] ( [Recno] [int] identity (1, 1) not null, [Stuid] [varchar] (10) Collate chinese_prc_ci_as not null, [Stuname] [varchar] (10) Collate chinese_prc_ci_as not null ) On [primary] Go 1. Check the repeated values of one or more columns.(Only the value of the reco
There is A field ldquo; name rdquo; in Table A, and the value of ldquo; name rdquo; between different records may be the same, now you need to query the records in the table, and the ldquo; name rdquo; value has repeated items; SelectName, Count (*) fromAGroupByNameHavingCount (*) gt; 1. If the gender is also the same, for example, the field "name" exists in table ", The "name" value may be the same
The following is an elaboration of the issue of duplicate record deletion. There are two duplicates of the record, one is a completely duplicate record, that is, all the fields are duplicate records, the second is some key fields duplicate
server| Repeat | Repeat the following to illustrate the issue of duplicate record deletion. There are two duplicates of the record, one is a completely duplicate record, that is, all the fields are duplicate records, the second is some key fields duplicate
In the system to a customer on-line found that there is a table of duplicate data, the results by troubleshooting code to find that there is a problem with the business logic, after modifying the code needs to be in the database of data deduplication on CSDN to find a solution,do not delete the database on the wire as much as possible, and you should back up the database regardless of any action on the data
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