Dropping Unique constraint from MySQL table

Question

How can I drop the \"Unique Key Constraint\" on a column of a MySQL table using phpMyAdmin?

Answer 1

The constraint could be removed with syntax:

ALTER TABLE

As of MySQL 8.0.19, ALTER TABLE permits more general (and SQL standard) syntax for dropping and altering existing constraints of any type, where the constraint type is determined from the constraint name: ALTER TABLE tbl_name DROP CONSTRAINT symbol;

Example:

CREATE TABLE tab(id INT, CONSTRAINT unq_tab_id UNIQUE(id));

-- checking constraint name if autogenerated
SELECT * FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE TABLE_NAME = 'tab';

-- dropping constraint
ALTER TABLE tab DROP CONSTRAINT unq_tab_id;

db<>fiddle demo