Databases
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POcombine tables related to each other by a linking table and not to worry if the linking table is missing some data
 

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  1. POcombine tables related to each other by a linking table and not to worry if the linking table is missing some data
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    <p>I have a simple relational database set up similar to the example below</p> <pre><code>[Customer] --&lt; [CGLink] &gt;-- [Order] Person: Alias Name(PK) A Bill B Ben C Bob D Jim E John CGLink: ID(PK) Alias Type 1 A W 2 A X 3 B W 4 B X 5 B Y 6 B Z 7 C Y 8 E Z Group: Type(PK) Group W Double-U X Eks Y Whai Z Zed </code></pre> <p>And I want to return a set of results like</p> <pre><code>Alias Name Group A Bill Double-U A Bill Eks B Ben Double-U B Ben Eks B Ben Whai B Ben Zed C Bob Whai D Jim E John Zed </code></pre> <p>As you can see Jim had no associated data in the linking table and I want to avoid having to place a row of dummy data that I can link all people to who don't have a group in order to let me return this data.</p> <p>The query I am using is</p> <pre><code>SELECT p.Alias, p.Name, g.Group FROM Person AS p, Group AS s, CGLink AS l WHERE (p.Alias=l.Alias AND l.Type=s.Type) ORDER BY p.Alias, p.Name; </code></pre> <p>This returns</p> <pre><code>Alias Name Group A Bill Double-U A Bill Eks B Ben Double-U B Ben Eks B Ben Whai B Ben Zed C Bob Whai E John Zed </code></pre> <p>Which as you can see, is missing Jim because he had no associated group. How can I obtain the results I really want?</p> <p>Cheers</p>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

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