MySQL Reference Manual for version 4.0.18.

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A.5.1 Case-Sensitivity in Searches

By default, MySQL searches are not case sensitive (although there are some character sets that are never case-insensitive, such as czech). That means that if you search with col_name LIKE 'a%', you will get all column values that start with A or a. If you want to make this search case sensitive, use something like INSTR(col_name, "A")=1 to check a prefix. Or use STRCMP(col_name, "A") = 0 if the column value must be exactly "A".

Simple comparison operations (>=, >, = , < , <=, sorting and grouping) are based on each character's "sort value". Characters with the same sort value (like E, e and é) are treated as the same character!

In older MySQL versions LIKE comparisons were done on the uppercase value of each character (E == e but E <> é). In newer MySQL versions LIKE works just like the other comparison operators.

If you want a column always to be treated in case-sensitive fashion, declare it as BINARY. See section CREATE TABLE.

If you are using Chinese data in the so-called big5 encoding, you want to make all character columns BINARY. This works because the sorting order of big5 encoding characters is based on the order of ASCII codes.



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