mysql - 删除 MySQL 表是否也会自动删除该表的索引？

Question

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Answer 1

是的。它删除索引。这可以验证:

CREATE TABLE table1 (foo INT);
CREATE INDEX ix_table1_foo ON table1 (foo);
CREATE INDEX ix_table1_foo ON table1 (foo); -- fails: index already exists.
DROP TABLE table1;
CREATE TABLE table1 (foo INT);
CREATE INDEX ix_table1_foo ON table1 (foo); -- succeeds: index does not exist.

您也可以通过查看 information schema 来验证它。 :

CREATE TABLE table1 (foo INT);
CREATE INDEX ix_table1_foo ON table1 (foo);

SELECT COUNT(*)
FROM information_schema.STATISTICS
WHERE INDEX_NAME = 'ix_table1_foo';  -- returns 1

DROP TABLE table1;

SELECT COUNT(*)
FROM information_schema.STATISTICS
WHERE INDEX_NAME = 'ix_table1_foo';  -- returns 0