tag:blogger.com,1999:blog-5401085822056220912024-09-09T19:14:19.861-07:00T-SQL Union allAnonymoushttp://www.blogger.com/profile/06731273299234474960noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-540108582205622091.post-64453366379252509052010-05-10T11:30:00.001-07:002015-03-24T13:30:55.838-07:00SQL “Union” and “Union All”<link href="file:///D:%5CDOCUME%7E1%5CFCHOWD%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_filelist.xml" rel="File-List"></link><link href="file:///D:%5CDOCUME%7E1%5CFCHOWD%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_themedata.thmx" rel="themeData"></link><link href="file:///D:%5CDOCUME%7E1%5CFCHOWD%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_colorschememapping.xml" rel="colorSchemeMapping"></link><style>
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<b><span style="font-size: large;">SQL “Union” and “Union All”</span></b></div>
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<br /></div>
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SQL union combines two or more tables. Let’s say, I have two tables <span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">Persons_BD</span><span style="color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;"> and <span style="background: none repeat scroll 0% 0% silver;">Persons_</span>US</span></div>
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They both have similar column names that I will try to combine with Union query. Persons_US has data like: </div>
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: medium none;"><tbody>
<tr> <td style="border: 1pt solid black; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
P_Id</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
LastName</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
FirstName</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Address</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
City</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
1</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Chowdhury</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Pavel</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
3326 82ns Street</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Sandnes</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
2</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Chowdhury</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Nitol</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka Street</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka</div>
</td> </tr>
</tbody></table>
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<br /></div>
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And Person_BD have data like </div>
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: medium none;"><tbody>
<tr> <td style="border: 1pt solid black; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
P_Id</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
LastName</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
FirstName</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Address</div>
</td> <td style="border-color: black black black -moz-use-text-color; border-style: solid solid solid none; border-width: 1pt 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
City</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
2</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Chowdhury</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Nitol</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka Street</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
2</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Chowdhury</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Pavel</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.75pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka Street</div>
</td> <td style="border-color: -moz-use-text-color black black -moz-use-text-color; border-style: none solid solid none; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 95.8pt;" valign="top" width="128"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Dhaka</div>
</td> </tr>
</tbody></table>
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<br /></div>
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Now, if I run this query </div>
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<br /></div>
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<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">SELECT</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> FIRSTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: red; font-family: "Courier New"; font-size: 10pt;">' '</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> LASTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">AS</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">NAME</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">FROM</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> DBO</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">.</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;">PERSONS<o:p></o:p></span></div>
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<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">UNION<o:p></o:p></span></div>
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<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">SELECT</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;"> FIRSTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">+</span><span style="background: none repeat scroll 0% 0% silver; color: red; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">' '</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">+</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;"> LASTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">FROM</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;"> DBO</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">.</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">PERSONS1</span><span style="color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;"><o:p></o:p></span></div>
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<span style="color: teal; font-family: "Courier New"; font-size: 10pt; line-height: 115%;">The result set will be <o:p></o:p></span></div>
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: medium none;"><tbody>
<tr> <td style="border: 1pt solid black; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
NAME</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Nitol Chowdhury</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Pavel Chowdhury</div>
</td> </tr>
</tbody></table>
<div class="MsoNormal">
However, if I use UNION ALL look the result set is different</div>
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<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">SELECT</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> FIRSTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: red; font-family: "Courier New"; font-size: 10pt;">' '</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> LASTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">AS</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">NAME</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">FROM</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> DBO</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">.</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;">PERSONS<o:p></o:p></span></div>
<div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">UNION ALL<o:p></o:p></span></div>
<div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
<span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">SELECT</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> FIRSTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: red; font-family: "Courier New"; font-size: 10pt;">' '</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">+</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> LASTNAME </span><span style="background: none repeat scroll 0% 0% silver; color: blue; font-family: "Courier New"; font-size: 10pt;">FROM</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;"> DBO</span><span style="background: none repeat scroll 0% 0% silver; color: grey; font-family: "Courier New"; font-size: 10pt;">.</span><span style="background: none repeat scroll 0% 0% silver; color: teal; font-family: "Courier New"; font-size: 10pt;">PERSONS1<o:p></o:p></span></div>
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: medium none;"><tbody>
<tr> <td style="border: 1pt solid black; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
NAME</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Pavel Chowdhury</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Nitol Chowdhury</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Nitol Chowdhury</div>
</td> </tr>
<tr> <td style="border-color: -moz-use-text-color black black; border-style: none solid solid; border-width: medium 1pt 1pt; padding: 0in 5.4pt; width: 108.9pt;" valign="top" width="145"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
Pavel Chowdhury</div>
</td> </tr>
</tbody></table>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
This is because UNION compare the tables and bring the result only the information that are common. </div>
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