表结构如

CREATE TABLE IF NOT EXISTS public.user (
id PRIMARY KEY,
name varchar(32) NOT NULL UNIQUE,
......
);

修改语句

alter table public.user alter name set data type varchar(52);

由于受“UNIQUE”条件的约束，如果直接执行语句将会报如下错误：

ROLLBACK 2350: Cannot alter type of column "name" since it is referenced in the constraint "C_UNIQUE_1"

所以要先删除“UNIQUE”约束

alter table wb_play.user drop CONSTRAINT C_UNIQUE_1 CASCADE;

再执行

alter table public.user alter name set data type varchar(52);

然后重新加上“UNIQUE”约束

alter table public.user add CONSTRAINT C_UNIQUE_1 UNIQUE(name);