CREATE TABLE test_change (a int , b int , c int ); // First change column a's name to a1. ALTER TABLE test_change CHANGE a a1 INT; // Next change column a1's name to a2, its data type to string, and put it after column b. ALTER TABLE test_change CHANGE a1 a2 STRING AFTER b; // The new table's structure is: b int, a2 string, c int. // Then change column c's name to c1, and put it as the first column. ALTER TABLE test_change CHANGE c c1 INT FIRST; // The new table's structure is: c1 int, b int, a2 string. // Add a comment to column a1 ALTER TABLE test_change CHANGE a1 a1 INT COMMENT 'this is column a1' ; |