Re: Case insensitive search in utf8 db
Posted by: Peter Brawley
Date: December 02, 2019 12:51PM

When the missing quote before the collate argument is supplied, this table treats our three test strings as equivalent, as expected ...

-- strings were copied through a text editor using utf8 charset
insert into wpersons set id='1', name='ΓΙΑΝΝΗΣ'; 
insert into wpersons set id='2', name='Γιαννης'; 
insert into wpersons set id='3', name='Γιάννης';

select name from wpersons where  name='ΓΙΑΝΝΗΣ';
+----------------+
| name           |
+----------------+
| ΓΙΑΝΝΗΣ        |
| Γιαννης        |
| Γιάννης        |
+----------------+

select name from wpersons where  name='Γιαννης';
+----------------+
| name           |
+----------------+
| ΓΙΑΝΝΗΣ        |
| Γιαννης        |
| Γιάννης        |
+----------------+

select name from wpersons where  name='Γιάννης';
+----------------+
| name           |
+----------------+
| ΓΙΑΝΝΗΣ        |
| Γιαννης        |
| Γιάννης        |
+----------------+

That says that your collation problem arises from the data that went into your table, or the process by which it was entered.

Run this on wpersons ...

select name, hex(name), length(name), char_length(name) from wpersons;
+----------------+------------------------------+--------------+-------------------+
| name           | hex(name)                    | length(name) | char_length(name) |
+----------------+------------------------------+--------------+-------------------+
| ΓΙΑΝΝΗΣ        | CE93CE99CE91CE9DCE9DCE97CEA3 |           14 |                 7 |
| Γιαννης        | CE93CEB9CEB1CEBDCEBDCEB7CF82 |           14 |                 7 |
| Γιάννης        | CE93CEB9CEACCEBDCEBDCEB7CF82 |           14 |                 7 |
+----------------+------------------------------+--------------+-------------------+

length() returns the byte count, char_length() the char count.

Now let's see the result from this query on problem table with ... limit 3 added to the query.


(BTW the table isn't a valid relational table---no primary key.)



Edited 1 time(s). Last edit at 12/02/2019 12:51PM by Peter Brawley.

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Re: Case insensitive search in utf8 db
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