mysql empty a table

-- If you do not need a condition or limit the rows:
TRUNCATE TABLE tblYourTable; -- Not Foreign key constrained

-- Or

SET FOREIGN_KEY_CHECKS = 0;

TRUNCATE YourTable1;
TRUNCATE YourTable2;

SET FOREIGN_KEY_CHECKS = 1;

-- --------------------------------------------------------
-- Otherwise:
DELETE FROM tblYourTable WHERE condition;

-- Or

DELETE FROM tblYourTable LIMIT row_count;