#Mysql collate how to#
#Mysql collate full#

Is it somehow converted to the collation latin1_german1_ci? SELECT FROM myTable WHERE emailaddress IN ('', '') COLLATE utf8. What happens in the where clause? Has the selected string from column `c` collation latin1_swedish_ci? but then the comparison should give an error. In MySQL, I can specify the collation if I have a standard WHERE clause like this: SELECT FROM myTable WHERE emailaddress '' COLLATE utf8generalci However the following fails if I have multiple email addresses in a WHERE-IN clause. You can also specify a collation in your queries that will override any collation that has been applied at the database, table, or column levels. It can be applied at the server level, the connection level, the database level, the table level, and even at the column level. So I see two collates, swedish for the values of the column `c` and german1 for the search term. In MySQL, collation can be applied at many levels. IIRC _latin1 'bar' collate latin1_german1_ci is a character set introducer which defines (forces?) the charset and collation of the string 'bar'. Select c from swedish where c = _latin1 'bar' collate latin1_german1_ci

#Mysql collate how to#

I've seen in the docs how to do this - it works with 'ber' or 'yac' as well I need to do a case- and accent-insensitive search with ASCII search values, I would like to use the collation latin1_german1_ci which treats those 3 couples as the same. I have a table with latin1 charset and latin1_swedish_ci collation CREATE TABLE `swedish` (Įngine, charset and collation are given constraints. To me a collation makes sense only in the context of a comparison of two text strings. They allow for example to consider 'Mane' the same as 'Manè'. and MySQL 5.6, 5.7, and 8.0, and the behavior was the same across all of them.As I understand, collations are sets of rules to sort and compare strings, I tested this on dbfiddle against MariaDB 10.2 and 10.3. This enables you to change between InnoDB and MyISAM table types even though the row formats supported by the two engines are different.

The information is retained so that if you change storage engines, collations or other settings using an ALTER TABLE statement, the original table options specified are retained. The original CREATE TABLE statement, including all specifications and table options are stored by MySQL when the table is created. Adding the COLLATE clauses makes the operation very clear and unambiguous.Īlso, the documentation for CREATE TABLE Statement Retention states:

#Mysql collate full#

Yes, there are defaults explicitly declared for the table, but what if a) the table defaults aren't respected, and/or b) whatever is reading the DDL wants to know everything about a column as it parses the column, as opposed to needing to read the full table DDL first and potentially go back to apply defaults. Yes, character sets have default collations, but defaults can change over time or between contexts. On the other hand, a collation works with only 1 character set, so specifying the collation does imply the character set. Why just the COLLATE statement and not also CHARACTER SET? That is most likely due to character sets working with 1 or more collations, so specifying the character set does not imply the collation. I'm not sure why CHARACTER SET became explicitly stated in the stored version of the CREATE TABLE t1 statement, but I think I know why COLLATE did for CREATE TABLE t2: once you submit the statement, that's what it gets translated into as it's being processed. ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin `baz` char(80) COLLATE utf8_bin DEFAULT NULL `bar` char(64) COLLATE utf8_bin DEFAULT NULL,

`foo` char(60) COLLATE utf8_bin DEFAULT NULL, `baz` char(80) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL `bar` char(64) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL, `foo` char(60) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,

Now, I created the two tables as you have them in the question, and that resulted in the following: SHOW CREATE TABLE t1 New columns in t1 will be CHARSET=utf8 (because that was specified as default for the table), but will also be COLLATE=utf8_general_ci (because this should be the default for the utf8 character set) New columns in t2 will be CHARSET=utf8 and COLLATE=utf8_bin (because they were specified as defaults for the table), but IF a string column is added that does not specify either CHARSET or COLLATE clauses: the behavior and performance will be different. In their current form: the behavior and performance of t1 and t2 should be identical,