PostgreSQL SELECT INTO和INSERT INTO SELECT 两种表复制语句

SELECT INTO和INSERT INTO SELECT两种表复制语句都可以用来复制表与表之间的数据，但是它们之间也有区别。

建表语句：

bas_custom_rel表

CREATE TABLE "public"."bas_custom_rel" (
"uuid" int8 NOT NULL,
"kunnrkh" varchar(100) COLLATE "default",
"zfdel" varchar(1) COLLATE "default",
"hkunnrkh" varchar(100) COLLATE "default",
"create_time" timestamp(6) NOT NULL,
"modify_time" timestamp(6),
"sync_status" varchar(1) COLLATE "default",
"sync_time" timestamp(6),
"ret_code" varchar(100) COLLATE "default",
"ret_message" varchar(5000) COLLATE "default",
"z_date" timestamp(6),
CONSTRAINT "pk_bas_custom_rel" PRIMARY KEY ("uuid")
)
cust_rel表：

CREATE TABLE "public"."cust_rel" (
"son" varchar(255) COLLATE "default",
"pp" varchar(255) COLLATE "default"
)

1. INSERT INTO FROM语句

　语句形式为：Insert into Table2(field1,field2,…) select value1,value2,… from Table1

　要求目标表Table2必须存在，由于目标表Table2已经存在，所以我们除了插入源表Table1的字段外，还可以插入常量。示例如下：

INSERT INTO bas_custom_rel (
uuid,
kunnrkh,
zfdel,
hkunnrkh,
create_time,
modify_time,
sync_status,
sync_time,
ret_code,
ret_message,
z_date
) SELECT
nextval('cust_rel_seq') AS uuid,
son,
'' AS zfdel,
coalesce(pp,'-1') AS pp,
now() as create_time,
NULL AS modify_time,
0 AS sync_status,
NULL AS sync_time,
0 as ret_code,
'' AS ret_message,
now()
FROM
cust_rel;
2.SELECT INTO FROM语句

　语句形式为：SELECT vale1, value2 into Table2 from Table1

　要求目标表Table2不存在，因为在插入时会自动创建表Table2，并将Table1中指定字段数据复制到Table2中。示例如下：

postgres=# drop table tb101; DROP TABLE
postgres=#
postgres=# select * into tb101 from tb100 where id<5; SELECT 4
postgres=#
postgres=# select * from tb101; id | name ----+------ 1 | aa 2 | aa 3 | aa 4 | aa (4 rows)
3、复制表结构及数据到新表
CREATE TABLE 新表 SELECT * FROM 旧表
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作者：小城南
来源：CSDN
原文：https://blog.csdn.net/cainiaobulan/article/details/83147418
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