UTF8_BIN vs. UTF8_GENERAL_CI: What are the Key Differences in Collation?

Binary Collation Effects: A Deeper Dive

While exploring the binary collation, a question arose regarding the practical differences between utf8_bin and utf8_general_ci collations. Let's delve deeper to identify these distinctions:

• Sorting Order: As mentioned, utf8_bin compares strings based solely on byte values, which differs from the natural sort order of utf8_general_ci, leading to potential unexpected sorting results (e.g., umlauts at the end of the alphabet).
• Case Sensitivity: utf8_bin is strictly case sensitive, meaning case-insensitive comparisons (e.g., uppercase and lowercase letters treated as equal) are not possible. This differs from utf8_general_ci, which ignores case differences for comparison purposes.
• Equality with Diacritics: The utf8_bin collation does not recognize diacritics as equivalent to the base character (e.g., 'A' and 'Ä' are distinct). In contrast, utf8_general_ci treats characters with diacritics as equivalent to their base characters, allowing for broader matches and equality checks.

Additionally, the binary collation provides a performance advantage for exact matches, as it simplifies string comparisons. However, for sorting purposes, indexes created with binary collations may not yield the expected results.

In summary, the primary differences between utf8_bin and utf8_general_ci collations lie in their sorting order, case sensitivity, and diacritic handling. These distinctions dictate when it is appropriate to use each collation based on the specific requirements of a given application.

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