c# generate barcode QUERYING MULTIPLE DATABASE OBJECTS AND MANIPULATING RESULT SETS in Font

Creator USS Code 39 in Font QUERYING MULTIPLE DATABASE OBJECTS AND MANIPULATING RESULT SETS

CHAPTER 6 QUERYING MULTIPLE DATABASE OBJECTS AND MANIPULATING RESULT SETS
Making Code 39 Full ASCII In None
Using Barcode drawer for Font Control to generate, create USS Code 39 image in Font applications.
www.OnBarcode.com
Make Barcode In None
Using Barcode encoder for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
The following pair of queries shows the number of rows with null and non-ProductSubcategoryID column values in the Product table. As you can see, there are 209 Product rows with null ProductSubcategoryID values. This is out of a total of 504 (209 + 295) rows in the Product table. SELECT Count(*) 'Null SubcategoryID values in Product' FROM Production.Product WHERE ProductSubcategoryID IS NULL Null SubcategoryID values in Product -----------------------------------209 SELECT Count(*) 'Non-null SubcategoryID values in Product' FROM Production.Product WHERE ProductSubcategoryID IS NOT NULL Non-null SubcategoryID values in Product ---------------------------------------295 The next SELECT statement and result set shows the outcome of a right join between the ProductSubcategory and Product tables. The SELECT statement does a lookup of Name column values in the ProductSubcategory table based on ProductSubcategoryID column values in the Product table. The Product table is on the right so that all of its rows enter the result set whether or not they match rows in the ProductSubcategory table. All 209 rows with null ProductSubcategoryID column values in the Product table occur for rows with ProductID column values that are less than those for rows with non-null ProductSubcategoryID column values. Because the following SELECT statement contains an ORDER BY clause that sorts according to ascending ProductID values, rows with null values for the Name column of the ProductSubcategory table occur before rows with non-null Name column values. The syntax for a right join is nearly identical to an inner join. In fact, the only difference is the keyword or phrase denoting the type of join. With a right join, you designate the type of join with either RIGHT JOIN or RIGHT OUTER JOIN. With an inner join, you specify the join with either JOIN or INNER JOIN. SELECT TOP 5 ProductID, p.Name 'Product name', sc.Name 'Subcategory name' FROM Production.ProductSubcategory sc RIGHT JOIN Production.Product p ON sc.ProductSubcategoryID = p.ProductSubcategoryID ORDER BY ProductID ProductID ----------1 2 3 4 316 Product name --------------------Adjustable Race Bearing Ball BB Ball Bearing Headset Ball Bearings Blade Subcategory name ---------------NULL NULL NULL NULL NULL
Generate Barcode In None
Using Barcode printer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Creating DataMatrix In None
Using Barcode encoder for Font Control to generate, create Data Matrix 2d barcode image in Font applications.
www.OnBarcode.com
CHAPTER 6 QUERYING MULTIPLE DATABASE OBJECTS AND MANIPULATING RESULT SETS
Generating Code39 In None
Using Barcode creator for Font Control to generate, create Code 3 of 9 image in Font applications.
www.OnBarcode.com
Making UCC.EAN - 128 In None
Using Barcode printer for Font Control to generate, create UCC-128 image in Font applications.
www.OnBarcode.com
If the direction of the join changes from a right join to a left join and all the other syntax remains the same, then only rows from the Product table with a match based on ProductSubcategoryID column values will enter the result set. As a consequence, all the Subcategory name column values in the result set will have non-null values. To redesign the SELECT statement for this outcome, all you need to do is change RIGHT JOIN to LEFT JOIN. The following SELECT statement and result set show the syntax and outcome of a left join between the ProductSubcategory and Product tables based on ProductSubcategoryID column values. Notice all the Subcategory name column values in the result set are non-null. This is true for all Subcategory name values in the left join of the tables and not just the first five rows. The replacement of RIGHT JOIN with LEFT JOIN in the FROM clause within the SELECT statement only allows rows from the Product table with matching ProductSubcategoryID column values to enter the result set. SELECT TOP 5 ProductID, p.Name 'Product name', sc.Name 'Subcategory name' FROM Production.ProductSubcategory sc LEFT JOIN Production.Product p ON sc.ProductSubcategoryID = p.ProductSubcategoryID ORDER BY ProductID ProductID ----------680 706 707 708 709 Product name ------------------------HL Road Frame - Black, 58 HL Road Frame - Red, 58 Sport-100 Helmet, Red Sport-100 Helmet, Black Mountain Bike Socks, M Subcategory name ---------------Road Frames Road Frames Helmets Helmets Socks
Encoding Universal Product Code Version A In None
Using Barcode generator for Font Control to generate, create GTIN - 12 image in Font applications.
www.OnBarcode.com
Creating ANSI/AIM Code 93 In None
Using Barcode maker for Font Control to generate, create Uniform Symbology Specification Code 93 image in Font applications.
www.OnBarcode.com
Counting Rows
ANSI/AIM Code 39 Drawer In None
Using Barcode encoder for Online Control to generate, create ANSI/AIM Code 39 image in Online applications.
www.OnBarcode.com
Code39 Maker In Objective-C
Using Barcode creation for iPad Control to generate, create Code-39 image in iPad applications.
www.OnBarcode.com
In addition to listing rows that match a join criterion, you ll often need to aggregate rows that meet a join criterion. For example, you may wonder if all the non-null ProductSubcategoryID column values in the Product table match at least one ProductSubcategoryID column value in the ProductSubcategory table. You can answer this question by counting the ProductID column values for a left join between the ProductSubcategory and Product tables as shown in the following SELECT statement. Recall that there are just 295 non-null ProductSubcategoryID column values in the Product table. Therefore, if the count of the ProductID column values equals 295 (as it does), then all the ProductSubcategoryID column values in the Product table match at least one ProductSubcategoryID column value from the ProductSubcategory table. SELECT COUNT(p.ProductID) 'Product rows with non-null ProductSubcategoryID' FROM Production.ProductSubcategory sc LEFT JOIN Production.Product p ON sc.ProductSubcategoryID = p.ProductSubcategoryID With many query designs, it is not uncommon to need some kind of aggregated summary. This kind of need regularly exists when working with outer joins. The following SELECT statement computes a count of the number of matching rows by ProductSubcategoryID value for a left join between the ProductSubcategory and Product tables. The query reveals the distribution of matching rows by ProductSubcategoryID value. This type of query task gives you a chance to combine a left join with a GROUP BY clause and an aggregate function namely, COUNT. The left join automatically excludes all 209 rows from the Product table with null ProductSubcategoryID values. As a result, the sum across all 37 ProductSubcategoryID column values is 295. To conserve space, the listing from this query does not show, but you can easily generate the result set by running the last sample in OuterJoins.sql.
EAN / UCC - 13 Generator In Java
Using Barcode creation for Eclipse BIRT Control to generate, create EAN / UCC - 13 image in BIRT reports applications.
www.OnBarcode.com
Printing PDF417 In None
Using Barcode generation for Office Excel Control to generate, create PDF417 image in Office Excel applications.
www.OnBarcode.com
Generate Code 128 In Objective-C
Using Barcode maker for iPhone Control to generate, create USS Code 128 image in iPhone applications.
www.OnBarcode.com
Encode Code 3 Of 9 In None
Using Barcode maker for Software Control to generate, create Code 39 image in Software applications.
www.OnBarcode.com
QR Creation In None
Using Barcode creation for Word Control to generate, create QR Code JIS X 0510 image in Word applications.
www.OnBarcode.com
PDF-417 2d Barcode Creation In Java
Using Barcode generator for Android Control to generate, create PDF-417 2d barcode image in Android applications.
www.OnBarcode.com
Code39 Encoder In Java
Using Barcode creator for Java Control to generate, create Code 39 image in Java applications.
www.OnBarcode.com
GTIN - 128 Drawer In .NET Framework
Using Barcode creation for VS .NET Control to generate, create USS-128 image in Visual Studio .NET applications.
www.OnBarcode.com
UPCA Decoder In VB.NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Draw Barcode In C#.NET
Using Barcode generation for VS .NET Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.