If you don’t change the collation for a table the database’s collation will be used and so on. The default collation is inherited that is, if you don’t change the collation for a database the server’s default will be used. In MySQL you can set the default collation for server, database, table or column. You can even add your own collation to MySQL: Default Collation Mysql> create database wrong_collation character set utf8 collate latin2_czech_cs ĮRROR 1253 (42000): COLLATION 'latin2_czech_cs' is not valid for CHARACTER SET 'utf8' MySQL checks if the collation and the character set match. Every character set has one default collation which is used if the collation is not specified explicitly. So ‘latin1_danish_ci’ is a collation for charset ‘latin1’, for the Danish language and is case-insensitive.Įvery collation in MySQL is assigned to exactly one character set. The convention for a collation name in MySQL: first character set name, then the name of the language, finally the type of the collation (ci stands for case-insensitive, cs for case-sensitive, bin for binary collation). | latin1_spanish_ci | latin1 | 94 | | Yes | 1 | | latin1_general_cs | latin1 | 49 | | Yes | 1 | You can filter the list to show only collations for charset ‘latin1’: | latin1_general_ci | latin1 | 48 | | Yes | 1 | | latin1_german2_ci | latin1 | 31 | | Yes | 2 | | latin1_danish_ci | latin1 | 15 | | Yes | 1 | | latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 | | latin1_german1_ci | latin1 | 5 | | Yes | 1 | | koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 | | hp8_english_ci | hp8 | 6 | Yes | Yes | 1 | | dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 | | big5_chinese_ci | big5 | 1 | Yes | Yes | 1 | | Collation | Charset | Id | Default | Compiled | Sortlen | and MySQL 5.6, 5.7, and 8.0, and the behavior was the same across all of them.To list all collations available in MySQL, use 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: 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,
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