Not really a problem with the fact that numbers are first in an alphanumeric sort, but drawing to your attention here as we will explore changing this behavior to show some added benefit of our methodology.Ģ. As another learning experience, you can probably explore sorting this text (beginning with numbers) to correctly align with numerical values just with a suffix however, we will continue to keep heading down our original path where these values should be considered as text.
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The third is another example for our complex case as values with numeric only data on both sides of "-" will need to be treated/sorted as numeric so that for example United States zip+4 style postal code 45458-1234 would be sorted with shortened code 45458 as they would as text but additionally in the correct numerical sequence with the remainder of the data.Īside from wanting these separated, note how the grouping of alphanumeric and numeric only data causes seemingly incorrect numerical ordering. Second example also plants the seed for our more complex need of sorting on either side of a separator like hyphen ("-"). Select all Open in new window 3ĚUTĚ-1014 14 ISLĚ-987 Since the natural sort order above is correct for alphanumerically sorting a text column, let's take a look at what is wrong. What's wrong with the natural sort order? Now that our data is setup and our baseline (natural) sorting is established as seen in our data section, we can start to examine things further.ġ.
Results should appear similar to the below, barring any differences in auto-increment id: Select id, country, postalcode from country_postalcodes order by postalcode To test your data inserted ok and see the default textual sort, execute the following SQL statement:
Insert sample data into table from previous step. Therefore, to play along you can use the following steps in MySQL to setup the sample data being referenced:Ī column for string data and a primary key will do, but let's try a table of postal codes by country to give a more real life example of the kind of unstructured data we may have to live with.Ĭreate table `country_postalcodes` ( `id` integer unsigned not null auto_increment, `country` varchar(3) not null, `postalcode` varchar(10) not null, primary key(`id`) )
+if a hyphen does exist, sort needs to treat text and numbers on either side of hyphen separatelyįrom this point forward, I will reference the above data scenario as table country_postalcodes. +sorting needs to order text and numbers separately More experience on creating and executing DDL and other statements for T-SQL are also required as some code is only shown in MySQL syntax.ĭownload MS SQL Server Express and Management Tools Optionally, for those wanting to play with T-SQL examples as well, then MS SQL Server and a tool such as SQL Server Management Studio (SSMS) are also pre-requisites.
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Please note that, although experience can be varied, all will need to have MySQL Server, a tool such as MySQL Query Browser, and a basic knowledge of how to execute SQL statements as pre-requisites.ĭownload MySQL Community Server and GUI Tools
Custom Sorting in MySQL: Using IsNumeric() UDF.
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