SQL Server TSQL Coding Conventions, Best Practices, and Programming Guidelines - SQL Server Performance
Try to avoid wildcard characters at the beginning of a word while searching using the LIKE keyword, as that results in an index scan, which defeats the purpose of an index. I decided to write this article in order to put together some of the database programming best practices so that my fellow DBAs and database developers can benefit!Here are some programming guidelines and best practices, keeping quality, performance and maintainability in mind
OR GIVE ME A EXAMPLE TO KNOW HOW TO DOTHANK YOU VERY MUCH!! Dave Oct 27, 2009 at 9:50 PM 1 Comments Hi J.D,If you can join ECRPYHS and ECRHDHS, it should be easy to join PAYINFO as well. It doesn't happen all that often (most of my SQL is fairly simple), but every now and then someone shows me something that just rocks my world, whether it be the power of Indexing or just something as simple as using UNION ALL instead of UNION
How to save data from a DataSet into a T-SQL table - CodeProject
That entire page of data is sent back in a single dataset with multiple tables which gets processed then submitted to the database via xml using this function. License This article, along with any associated source code and files, is licensed under The Common Development and Distribution License (CDDL) Share email twitter facebook linkedin reddit google+ About the Author Sandeep Aparajit Software Developer (Senior) United States Sandeep has 9+ yrs of IT experience
Using Static SQL
If you set the isolation level of the main transaction to SERIALIZABLE, changes made by its autonomous transactions are not visible to the main transaction when it resumes: SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; Controlling Autonomous Transactions The first SQL statement in an autonomous routine begins a transaction. You use them when you want to perform a query in one subprogram, and process the results in a different subprogram (possibly one written in a different language)
The FIRST function returns the value of expression expr when evaluated in the first row of the group of rows mapped to the pattern variable that is specified in expr. Row pattern quantifiers are referred to as greedy; they will attempt to match as many instances of the regular expression on which they are applied as possible
Stairway to T-SQL DML Level 12: Using the MERGE Statement - SQLServerCentral
Prior to showing you my MERGE statement I need to create and populate my target CurrentListing table, as well as create a table that will contain the monthly current listings I get from my another source. To maintain my CurrentListing table all I need to do is create the right MATCHED and NOT MATCHED conditions to determine when to do an INSERT or UPDATE, and then include a new NOT MATCHED BY SOURCE condition to perform the DELETE operation
Example queries: SELECT * FROM sp ORDER BY 3 DESC sno pno qty S1 P1 NULL S3 P1 1000 S3 P2 200 S2 P1 200 SELECT name, city FROM s ORDER BY name name city John London Mario Rome Pierre Paris SELECT * FROM sp ORDER BY qty DESC, sno sno pno qty S1 P1 NULL S3 P1 1000 S2 P1 200 S3 P2 200 Expressions In the previous subsection on basic Select statements, column values are used in the select list and where predicate. SQL Special Constructs SQL supports a set of special expression constructs: CAST(exp-1 AS data-type) Converts the value - exp-1, into the specified date-type
The SQL SELECT Statement
An RDBMS performs all the basic functions of the DBMS software mentioned above along with a multitude of other functions that make the relational model easier to understand and to implement. The join operation is very powerful because it allows system users to investigate relationships among data elements that might not be anticipated at the time that a database is designed
Comparison of different SQL implementations
Instead, a MSSQL 2000-specific syntax was needed: SELECT TOP n columns FROM tablename ORDER BY key ASC The TOP construct is still available in MSSQL 2008, and it's handy for casual SQL work. Standard Optional feature T171 defines LIKE clause in table definition: CREATE TABLE t2 ( LIKE t1 ) The DBMS may support an extension of this (feature T173) which allows for more table properties to be copied: CREATE TABLE t2 ( LIKE t1 INCLUDING IDENTITY INCLUDING DEFAULTS INCLUDING GENERATED ) If INCLUDING DEFAULTS is not specified, column defaults will not be part of t2; likewise with IDENTITY and GENERATED properties
sql - How can I have multiple common table expressions in a single SELECT statement? - Stack Overflow
If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon. WITH cte1 AS ( SELECT * from cdr.Location ) select * from cte1 Is it possible to declare and use more than one cte in the same SELECT? ie this sql gives an error WITH cte1 as ( SELECT * from cdr.Location ) WITH cte2 as ( SELECT * from cdr.Location ) select * from cte1 union select * from cte2 the error is Msg 156, Level 15, State 1, Line 7 Incorrect syntax near the keyword 'WITH'
For example, SELECT * FROM sp sno pno qty S1 P1 NULL S2 P1 200 S3 P1 1000 S3 P2 200 The * delimiter will retrieve just the columns of a single table when qualified by the table name. Contents: sno name city S1 Pierre Paris S2 John London S3 Mario Rome The WHERE clause filters the rows of the FROM table to use those whose city column contains Rome
SQL SELECT DISTINCT Statement
Below is a selection from the "Customers" table: CustomerID CustomerName ContactName Address City PostalCode Country 1 Alfreds Futterkiste Maria Anders Obere Str. The SQL SELECT DISTINCT Statement In a table, a column may contain many duplicate values; and sometimes you only want to list the different (distinct) values
For example, if we have a table for recording customer information, then the columns may include information such as First Name, Last Name, Address, City, Country, and Birth Date. Given that there is no way for the database vendor to know ahead of time what your data storage needs are, you will for sure need to create tables that fit your needs in the database
sql - How to get data from two databases in two servers with one SELECT statement? - Stack Overflow
Steps around creating and using a linked server are: On your "main" MSSQL server create two linked servers to the servers that contains the two databases or as you said database A and database B. You are in essence saying: "Put these two sets of varying rows together based on their column logic matching." But you were mentioning connection strings so I was curious if you would want to do it in a type of code method like .NET? I could provide an idea for that too possibly
However, the easiest and the most clean way is to use JOIN clause in the DELETE statement and use multiple tables in the DELETE statement and do the task. -- Check the content of the table SELECT * FROM Table1 SELECT * FROM Table2 GO As you can see that using JOIN clause in DELETE statement it makes it very easy to update data in one table from another table
-- Check the content of the table SELECT * FROM Table1 SELECT * FROM Table2 GO As you can see that using JOIN clause in UPDATE statement it makes it very easy to update data in one table from another table. However, the easiest and the most clean way is to use JOIN clause in the UPDATE statement and use multiple tables in the UPDATE statement and do the task
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