sql count records in table

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

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.*

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

SQL Optimization-count, table join sequence, conditional order, in, exist, countexist 1. About count I have read some articles about count (*) and count (Column). Is the efficiency of count (column) higher than that of count? In fact, I personally

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 =

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>

This article introduces how to use havinggroupby and various selectin joint queries to filter the SQL language names of Repeated Records in different ways. This article introduces how to use having group by and various select in joint queries to

Original post address: http://www.cnblogs.com/phpliu/archive/2010/06/21/1761726.html For example:ID name value1 A PP2 A PP3 B III4 B PP5 B PP6 c pp7 c pp8 C IIIID is the primary keyThis result is required.ID name value1 A PP3 B III4 B PP6 c pp8 C