PHP + MySQL calculates the number of records for each table in the database and sorts the records in descending order. PHP + MySQL calculates the number of records for each table in the database and sorts the records in descending order, mysql
In the practical application, often need to implement in a query statement to display more than one table of data, this is called a multiple table data record connection query, referred to the next year will be the query.
When you implement a
The SQL statement I used:
Delete from fp_sgfpxxWhere fphm in (select fphm from fp_sgfpxx group by fphm having count (fphm)> 1)And rowid not in (select min (rowid) from fp_sgfpxx group by fphm having count (fphm)> 1)
Delete duplicate invoice
Translator: ye Jinrong (imysql # imysql.com), source: imysql.com, please reprint it. Cause: It is too slow to make count (*) Statistics on the innodb table, so try to see if you can hurry up. Symptom: Let's take a look at several test cases. 1. Test
Share the following method of deleting duplicate records in a database with an SQL statement.For example, there is now a person table (table name: peosons)If you want to name, ID, address, the three fields exactly the same record querySelect p1.*
The example in this article describes the method by which Php+mysql counts the number of records in each table in the library and in descending order. Share to everyone for your reference, as follows:
This is a simple code that implements the
Webjxcom prompt: for example, if you want to query records with the same name, ID card number, and address in the current table (table name: peosons), select P1. * from persons P1, persons P2 where p1.idp2. ID and p1.cardid = p2.cardid and p1.pname =
How to find out the duplicate records of field values in the same table(2013-03-25 11:28:51)reproduced For example, there is now a table (table name: peosons) If you want to name, social Security number, address the three fields exactly the same
Problem description
In the production database, the data of one table is 1 billion level, and that of the other table is 10 billion level. The data of other tables is also quite large. I didn't know that these tables had such a large amount of data
The number of records in the database table is:
Sql> Select COUNT (*) from table_name t;
COUNT (*)----------6873
1, using the statistical results of COUNT (*):
Sql> alter session Set Nls_language = "American";
Session altered.
Sql> set timing on;Sql>
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