How Can I Sort Varchar Columns Containing Numeric Values in MySQL?

Numeric Sorting of Varchar Columns in MySQL

When dealing with varchar columns that contain numeric values, sorting them as numbers can be a challenge. One approach to address this is by using the expression "* 1".

Using "* 1" for Numeric Sorting

Consider a table with a varchar column called "number_as_char" containing values such as "17.95", "199.95", and "139.95". To sort this column numerically, you can use the following query:

<code class="mysql">SELECT *
FROM tbl
ORDER BY number_as_char * 1;</code>

The "* 1" expression effectively converts the varchar values to numeric values. It allows you to sort the column as numbers, regardless of leading zeros or other non-numeric characters.

Benefits of Using "* 1"

Using the "* 1" expression offers several advantages:

• Robustness: It can handle situations where some rows have purely non-numeric data.
• Accuracy: It helps avoid underflow when choosing an appropriate casting type.
• Flexibility: It strips numeric portions from alphanumeric data, allowing for sorting of values like "123A" and "125A".

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