lightdb 支持兼容Oracle的to_clob函数

文章目录

概述

在信创移植的SQL语句中,有来源于Oracle数据库的SQL语句。

在ORACLE PL/SQL包中,你可以使用TO_CLOB(character)函数将RAW、CHAR、VARCHAR、VARCHAR2、NCHAR、NVARCHAR2、CLOB值转换为CLOB。

因此在LightDB 23.3版本中实现了对TO_CLOB函数的支持。

案例演示

环境准备

复制代码
create database test_oracle with lightdb_syntax_compatible_type  oracle;
\c test_oracle

使用TO_CLOB函数

复制代码
lightdb@test_oracle=# CREATE TABLE testorafce_to_clob (
lightdb@test_oracle(# col_char CHAR(10),
lightdb@test_oracle(# col_varchar2 VARCHAR2(20),
lightdb@test_oracle(# col_varchar VARCHAR(20),
lightdb@test_oracle(# col_nchar NCHAR(10),
lightdb@test_oracle(# col_nvarchar2 NVARCHAR2(20),
lightdb@test_oracle(# col_smallint smallint,
lightdb@test_oracle(# col_integer integer,
lightdb@test_oracle(# col_bigint bigint,
lightdb@test_oracle(# col_decimal decimal,
lightdb@test_oracle(# col_numeric numeric,
lightdb@test_oracle(# col_real real,
lightdb@test_oracle(# col_double double precision,
lightdb@test_oracle(# col_clob CLOB,
lightdb@test_oracle(# col_raw raw(10)
lightdb@test_oracle(# );
CREATE TABLE


lightdb@test_oracle=# INSERT INTO testorafce_to_clob (col_char, col_varchar2, col_varchar, col_nchar, col_nvarchar2, col_smallint, col_integer, col_bigint, col_decimal, col_numeric, col_real, col_double, col_clob, col_raw)
lightdb@test_oracle-# VALUES ('ABC1', 'Hello', 'world', N'中文', N'こんにちは', 1, 2, 3, 4, 5, 6, 7, 'This is a CLOB', 'AB');
INSERT 0 1
lightdb@test_oracle=# INSERT INTO testorafce_to_clob (col_char, col_varchar2, col_varchar, col_nchar, col_nvarchar2, col_smallint, col_integer, col_bigint, col_decimal, col_numeric, col_real, col_double, col_clob, col_raw)
lightdb@test_oracle-# VALUES ('ABC2', 'Hello', 'world', N'中文', N'こんにちは', 1, 2, 3, 4, 5, 6, 7, 'This is a CLOB', '1');
INSERT 0 1
lightdb@test_oracle=# INSERT INTO testorafce_to_clob (col_char, col_varchar2, col_varchar, col_nchar, col_nvarchar2, col_smallint, col_integer, col_bigint, col_decimal, col_numeric, col_real, col_double, col_clob, col_raw)
lightdb@test_oracle-# VALUES ('ABC3', 'Hello', 'world', N'中文', N'こんにちは', 1, 2, 3, 4, 5, 6, 7, oracle.to_clob('This is a CLOB'), '1AB456789');
INSERT 0 1


lightdb@test_oracle=# SELECT  oracle.to_clob(col_char) AS clob_char,
lightdb@test_oracle-# oracle.to_clob(col_varchar2) AS clob_varchar2,
lightdb@test_oracle-# oracle.to_clob(col_varchar) AS col_varchar,
lightdb@test_oracle-# oracle.to_clob(col_nchar) AS clob_nchar,
lightdb@test_oracle-# oracle.to_clob(col_nvarchar2) AS clob_nvarchar2,
lightdb@test_oracle-# oracle.to_clob(col_clob) AS clob_clob,
lightdb@test_oracle-# oracle.to_clob(col_smallint) AS col_smallint,
lightdb@test_oracle-# oracle.to_clob(col_integer) AS col_integer,
lightdb@test_oracle-# oracle.to_clob(col_bigint) AS col_bigint,
lightdb@test_oracle-# oracle.to_clob(col_decimal) AS col_decimal,
lightdb@test_oracle-# oracle.to_clob(col_numeric) AS col_numeric,
lightdb@test_oracle-# oracle.to_clob(col_real) AS col_real,
lightdb@test_oracle-# oracle.to_clob(col_double) AS col_double,
lightdb@test_oracle-# oracle.to_clob(col_raw) AS clob_nclob
lightdb@test_oracle-# FROM testorafce_to_clob order by col_char asc;
 clob_char  | clob_varchar2 | col_varchar |  clob_nchar  | clob_nvarchar2 |   clob_clob    | col_smallint | col_integer | col_bigint | col_decimal | col_numeric | col_real | col_double | clob_nclob 
------------+---------------+-------------+--------------+----------------+----------------+--------------+-------------+------------+-------------+-------------+----------+------------+------------
 ABC1       | Hello         | world       | 中文         | こんにちは     | This is a CLOB | 1            | 2           | 3          | 4           | 5           | 6        | 7          | AB
 ABC2       | Hello         | world       | 中文         | こんにちは     | This is a CLOB | 1            | 2           | 3          | 4           | 5           | 6        | 7          | 01
 ABC3       | Hello         | world       | 中文         | こんにちは     | This is a CLOB | 1            | 2           | 3          | 4           | 5           | 6        | 7          | 01AB456789
(3 rows)

可以看出,在Oracle兼容模式下LightDB 23.3版本TO_CLOB函数支持了CLOB、字符型以及数值型到CLOB类型的转换。

相关推荐
小明铭同学12 分钟前
MySQL 八股文【持续更新ing】
数据库·mysql
Mr_Xuhhh22 分钟前
信号与槽的总结
java·开发语言·数据库·c++·qt·系统架构
Fireworkitte25 分钟前
Redis 源码 tar 包安装 Redis 哨兵模式(Sentinel)
数据库·redis·sentinel
qq_339282231 小时前
postgressql 如何修改模式的所有表的所有者
数据库
西岭千秋雪_2 小时前
Redis性能优化
数据库·redis·笔记·学习·缓存·性能优化
极限实验室2 小时前
INFINI Labs 产品更新 | INFINI Console 1.29.6 发布 – 优化监控图表异常毛刺等
数据库·产品
先睡2 小时前
优化MySQL查询
数据库·sql
小张是铁粉2 小时前
oracle的内存架构学习
数据库·学习·oracle·架构
专注API从业者2 小时前
构建淘宝评论监控系统:API 接口开发与实时数据采集教程
大数据·前端·数据库·oracle