本篇文章主要介绍了" Redshift 通过重新建表修改varchar60 到varchar90"，主要涉及到方面的内容，对于其他数据库感兴趣的同学可以参考一下：
首先需要知道的是redshift不支持SQL语法直接修改varchar(60) 到varchar(90)，但PostgreSQL和MySQL都支持。1.Post...
root@localhost [testdb]>create table t1(c1 int,c2 varchar(60));
root@localhost [testdb]>insert into t1 values(1,'aaa'),(2,'bbb');
root@localhost [testdb]>alter table t1 modify c2 varchar(90);
root@localhost [testdb]>desc t1;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| c1 | int(11) | YES | | NULL | |
| c2 | varchar(90) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
3.redshift如何修改varchar(60)到varchar(90)???
Steps：
(1)Acquire table DDL statement:
pg_dump -h dpp.cmergb1wezbs.us-west-2.redshift.amazonaws.com -U tnadmin -d analytics -p 5439 -s -t facts.auto_events >> auto_events.sql
(2)Create tmp table:
CREATE TABLE facts.auto_events_tmp (
event_name character varying(30),
date_id integer,
log_id character varying(60),
reg_vid character varying(50),
visitor_id character varying(60),
carrier character varying(64),
app_id character varying(60),
