Decoding Unicode Errors: Fixing Character Encoding Issues In SQL Server

Gustavo

23 Apr, 2025

Why does seemingly innocuous text often transform into a baffling sequence of characters, and what's the key to unlocking the true meaning hidden within?

The answer lies in understanding character encoding and the potential for misinterpretation during data transfer and storage, a common pitfall that can corrupt even the most carefully crafted digital communication.

The digital realm, with its reliance on ones and zeros, often struggles to represent the nuances of human language. Each character, from the simplest letter to the most complex symbol, must be translated into a numerical code that computers can understand. This translation process is where things can go awry. Different systems, applications, and databases may employ varying character encoding schemes, such as UTF-8, ASCII, or others. When these systems are not synchronized, or when data is not correctly interpreted according to its encoding, garbled text, also known as mojibake, appears. This often manifests as a series of seemingly random characters where the intended words should be. The phenomenon isn't exclusive to any particular platform; it can appear across different operating systems, in web browsers, email clients, and database systems. While the underlying causes can be complex, the core issue is consistent: a mismatch between how the data was encoded and how it is being decoded.

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In the world of databases, especially in environments like SQL Server 2017, understanding collation becomes crucial. Collation dictates how character data is sorted and compared. It defines the rules for character sets, case sensitivity, accent sensitivity, and width sensitivity. The default collation setting can heavily influence how character data is stored and retrieved. If the database is configured with a collation that doesn't align with the expected character encoding, the resulting data can easily become corrupted, exhibiting symptoms similar to those of general encoding errors.

Issue	Character Encoding Errors
Description	Occurs when characters are not interpreted correctly due to encoding mismatches.
Cause	Mismatched character encoding schemes between systems, applications, or databases.
Symptoms	Garbled text (mojibake), showing sequences of unexpected characters, often starting with "" or "".
Examples	Instead of "", the characters might appear as "".
Technical Context	In SQL Server 2017, this might relate to collation settings that are out of sync with expected encoding.
Troubleshooting	Verify character encoding settings in the source system, database, and target system. Examine HTTP headers for encoding details. Use tools to identify and convert incorrect character encodings. Adjust table charset to match with data
Fixing the Charset	One effective approach is to correct the character set within the table. This involves: Identifying the Current Encoding: Determine the current encoding of your table to understand the nature of the problem. Converting to the Correct Encoding: If the data in your table is incorrectly encoded, you may need to convert it to UTF-8 or a different encoding that supports all your characters. Altering Table Columns: Alter the specific columns in your table that store the textual data. For example, use SQL commands to modify the `CHARSET` of the column to a proper value, or set up data validation rules. Importing Data: When importing new data, set the encoding properly.
Prevention	Ensure all systems and applications use consistent character encoding. Specify character encoding in HTTP headers and meta tags. Validate data encoding during import and export. Back up your data before making major character set changes.
Tools	SQL Server Management Studio (SSMS) Character Encoding Converters Text editors with encoding options (e.g., Notepad++, Sublime Text)
Reference	Microsoft SQL Server Documentation