在特殊字符（不可见字符，如ASCII 0、控制字符、非法字符等）上，Oracle非常宽松，基本上可以写入任何数据，包括不符合编码规则的数据。而PostgreSQL则不然，必须符合该字符集的编码，比如在UTF8字符集下，输入的字符编码比如符合UTF8编码。

**Oracle**
字符集为GBK，创建数据表，插入特殊字符（0x00），没有问题
```
TEST-orcl@DESKTOP-V430TU3>drop table t_0x00 purge;

Table dropped.

TEST-orcl@DESKTOP-V430TU3>create table t_0x00(id int,c1 varchar2(200),c2 blob);

Table created.

TEST-orcl@DESKTOP-V430TU3>insert into t_0x00 values(1,chr(0),null);

1 row created.

TEST-orcl@DESKTOP-V430TU3>insert into t_0x00 values(2,'c1'||chr(0),null);

1 row created.

TEST-orcl@DESKTOP-V430TU3>insert into t_0x00 values(3,chr(0)||'c1',null);

1 row created.

TEST-orcl@DESKTOP-V430TU3>insert into t_0x00 values(4,'c1'||chr(0)||'c1',null);

1 row created.

TEST-orcl@DESKTOP-V430TU3>insert into t_0x00 values(5,'c1'||chr(0)||'c1',to_blob(HEXTORAW('550055')));

1 row created.

TEST-orcl@DESKTOP-V430TU3>
TEST-orcl@DESKTOP-V430TU3>select * from t_0x00 where c1 like '%'||chr(0)||'%';

ID C1                   C2
---------- -------------------- --------------------
         1
         2 c1
         3  c1
         4 c1 c1
         5 c1 c1                550055

TEST-orcl@DESKTOP-V430TU3>

```

**PostgreSQL**
字符集为UTF8，创建数据表，插入特殊字符（0x00），无法插入
```
[local:/data/run/pg12]:5120 pg12@testdb=# \encoding
UTF8

[local:/data/run/pg12]:5120 pg12@testdb=# drop table t_0x00;
insert into t_0x00 values(4,'c1'||E'\x00'||'c1',null);
insert into t_0x00 values(5,'c1'||E'\x00'||'c1','\x550055'::bytea);DROP TABLE
[local:/data/run/pg12]:5120 pg12@testdb=# create table t_0x00(id int,c1 varchar(200),c2 bytea);
CREATE TABLE
[local:/data/run/pg12]:5120 pg12@testdb=# 
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(1,E'\x00',null);
ERROR:  invalid byte sequence for encoding "UTF8": 0x00
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(1,chr(0),null);
ERROR:  null character not permitted
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(2,null,bytea '\x00');
INSERT 0 1
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(3,E'\x00'||'c1',null);
ERROR:  invalid byte sequence for encoding "UTF8": 0x00
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(4,'c1'||E'\x00'||'c1',null);
ERROR:  invalid byte sequence for encoding "UTF8": 0x00
[local:/data/run/pg12]:5120 pg12@testdb=# insert into t_0x00 values(5,'c1'||E'\x00'||'c1','\x550055'::bytea);
ERROR:  invalid byte sequence for encoding "UTF8": 0x00
[local:/data/run/pg12]:5120 pg12@testdb=# select * from t_0x00 where c1 like '%'||chr(0)||'%';
ERROR:  null character not permitted
[local:/data/run/pg12]:5120 pg12@testdb=#

```
在Oracle -> PG的迁移过程中，这些特殊字符是需要考虑的。

**参考资料**
N/A

ITPub博客

Oracle vs PostgreSQL Develop（26） - ASCII 0

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