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COLLATION_CHARACTER_SET_APPLICABILITY.COLLATION_NAME vs MariaDB FULL_COLLATION_NAME #6361

@rotdrop

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@rotdrop

In recent MariaDB version the following will not succeed (resp. always yields an empty result set):

$sql = <<<'SQL'
SELECT t.TABLE_NAME,
t.ENGINE,
t.AUTO_INCREMENT,
t.TABLE_COMMENT,
t.CREATE_OPTIONS,
t.TABLE_COLLATION,
ccsa.CHARACTER_SET_NAME
FROM information_schema.TABLES t
INNER JOIN information_schema.COLLATION_CHARACTER_SET_APPLICABILITY ccsa
ON ccsa.COLLATION_NAME = t.TABLE_COLLATION
SQL;

The reason is, that CCSA.collation_name in recent MariaDB versions (tested version: 10.11.7) only contains the short collation name without prepended character set, while TABLES.table_collation contains the long table name. For example, in the case of the newly introduced utf8mb4_uca1400_ai_ci the corresponding row from COLLATION_CHARACTER_SET_APPLICABILITY is (CSV export):

"COLLATION_NAME","CHARACTER_SET_NAME","FULL_COLLATION_NAME","ID","IS_DEFAULT"
"uca1400_ai_ci","utf8mb4","utf8mb4_uca1400_ai_ci","2304",

while the TABLES.TABLE_COLLATION holds the full collation name utf8mb4_uca1400_ai_ci.

It also seems that this is a recent change in MariaDB; one Ubuntu "Jammy" system I am using runs MariaDB 10.6.16 which only has the COLLATION_NAME and CHARACTER_SET_NAME in that table, and the collation name is the full name with the character set prepended.

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