nested queriesShow the city's non-Shanghai staff information:SELECT * from staff where warehouse number in (select warehouse number from warehouse where city! = ' Shanghai ')Displays the average sales amount and warehouse number information for employees in different warehouses, provided that the average sales amount is greater than 15000 or the maximum sales amount is less than 18000 and the average wage of all employees is greater than 800 of the warehouse area:Select warehouse Number, AVG (a
Ind_attribute.is_ Disabled as [is disabled] 4 from (5 select Tab_name,index_name, [Co_names]=stuff ((SELECT ', ' +[co_name ') from 6 (select Tab. Name as Tab_name,ind. Name as index_name,col.name as Co_name from sys.indexes IND 7 INNER JOIN Sys.tables tab on Ind. object_id = tab.object_id and Ind.type in (8) inner join sys.index_columns index_columns on tab.object_id = Index_colu mns.object_id and ind.index_id = index_columns.index_id 9 inner join sys.columns Col on tab.object_id = col.object_i
T-SQL query: CTE, T-SQL: CTE
I have seen a simple example of the with as Clause in two books. I have not found any relevant information on the Internet.
Summary:
[Batch update of large tables]
[Batch Delete large tables]
[Keep only one row for completely repeated rows]
-- Create a test TABLE -- drop table [tabName] SELECT * INTO [tabName] FROM sys. objectsSELEC
Label:1. View the user tableSelect from Sys.tables Select from where type='U' Select from where xtype='U' where type or xtype value:U = user table S = system table V = view FN = scalar function TF = table function P = stored procedure
TR = Trigger
D = defaults or Default constraints PK = PRIMARY KEY constraintF = FOREIGN KEY constraint UQ = UNIQUE constraint SELECT from Information_schema. TABLES2. View ViewSELECT * from Information_schema. Views3. View the table/view fieldsS
Part i:relational Databases and SQLChapter2, ensuring Your Database Structureis sound.Database Design GuidelinesWhat is a relational databaseRDBMS (A relational database management systems) relational databaseTablesTables is the mainstructures in the database. Each table always represents aSingle, Specificsubject.FieldsA field is thesmallest structure in the database, and it represents a characteristicof the subject ofthe table to which it belongs.RecordsA record Representsa unique instance of t
Label:There are three basic types of joins: Cross joins, Inner joins, and outer joins. The cross join has only one step-cartesian product; There are two steps in the inner join-Cartesian product, filtering, outer join has three steps-cartesian product, filtering, adding outer row.Inner joinsCode: SELECT e.empid, E.firstname, E.lastname, O.orderid
from as E
JOIN as O
on = O.empid; Another way to do this: SELECT e.empid, E.firstname, E.lastname, O.orderid
from as as O
WHERE = O.e
Http://www.cnblogs.com/dubing/archive/2011/12/09/2278090.htmlRecently the company has come to a very tiger DBA 10几 years of experience here is called Cai Teacher. Let us share the precious wealth that Cai Lao has brought to us, with the consent of our Chua. Welcome other DBAs to shoot bricks
Directory1. What is the execution plan? The execution plan is dependent on what information.2, unified SQL statement to reduce parsing overhead3. Reduce the
Directory1. What is the execution plan? The execution plan is dependent on what information.2, unified SQL statement to reduce parsing overhead3. Reduce the nesting of SQL statements4. Staging intermediate results using temporary table5. The OLTP system SQL statement must take a binding variable6. The spy problem of the bound variable of the tilted field7. Begin
The word booksearch may be unfamiliar to many developers. Many people have encountered this word, but they have not paid enough attention to it, so they have always ignored its existence.
The word booksearch may be unfamiliar to many developers. Many people have encountered this word, but they have not paid enough attention to it, so they have always ignored its existence.
The growth of SQL Server Cognition
1. I don't have to graduate or work for
Directory1. What is an execution plan? The information on which the execution plan depends.2. Unify SQL statement writing to Reduce parsing overhead3. Reduce SQL statement nesting4. Use "temporary table" to save intermediate results5. The SQL statement of the OLTP system must use the bound variable.6. Preview the variable bound to the skewed field7. The
The growth of SQL Server Cognition
1. I don't have to graduate or work for a long time. I only know the relationship between SQL and SQL Server Oracle and MySql. I usually think that SQL is SQL Server.
2. after several years of work, I have also written a lot of
Small Program Ape SQL Server Cognitive growth
1. Did not graduate or work not long, only know that there is a database, SQL such dongdong, unaware of the SQL and SQL Server Oracle, MySQL relationship, usually considered SQL is SQL
Tags: write generated bsp MySQL col alt units should be two kinds ofInput command:show variables like ' slow% ' You can find that Slow_query_log is OFF (default), indicating that the slow query log is not turned on Slow_query_log_file for slow query log file There are two ways to turn on the slow query log Method One: Temporarily open Set Global slow_query_log
Original: Set STATISTICS io and set STATISTICS time in SQL Server query performance optimizationIn recent times, has been exploring the SQL Server query performance issues, of course, also aimless search for a lot of information, but also from the online great God's articles learned a lot, here, to the great God salute
The growth of SQL Server Cognition 1. I don't have to graduate or work for a long time. I only know the relationship between SQL and SQL Server Oracle and MySql. I usually think that SQL is SQL Server.2. after several years of work, I have also written a lot of
Many of my friends may be making mistakes in performance optimization as described below. If you have any need, please refer to the mistakes in SQL Server query performance optimization to get out of the index.
Many of my friends may be making mistakes in performance optimization as described below. If you have any need, please refer to the misunderstanding of SQL
: This article mainly introduces ThinkPHP-SQL query statements. For more information about PHP tutorials, see. I. query method
ThinkPHP provides three basic query methods: string condition query, index array condition query, and o
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