Question

I have a few lines of code in postgreSQL which I would like to use to query an Oracle database with the same tables and columns.

However the postgres code isn't working in sql developer and returns an error. The code looks like this:

SELECT * FROM file WHERE file_name IS NOT NULL 
AND file_name ~ '[\u0000-\u001f]|^$|^ | | $';

And

SELECT * FROM file WHERE file_name IS NOT NULL AND
CASE WHEN file_name LIKE '\\%' THEN right(file_name, -1) 
ELSE file_name END ~ '^[.]|[.]$';

I'm having trouble converting the ~ and the right(file_name, -1) parts of the code to run them in sql developer.

Any help is greatly appreciated.

Answer 1

您需要使用Oracle的substr()代替Postgres的right()
而不是regexp_like()函数，而不是~（区分大小写的正则表达式，如运算符），而将'c'作为3d参数（意味着大小写，尽管可以省略）：

SELECT * FROM file 
WHERE 
  file_name IS NOT NULL 
  AND
  REGEXP_LIKE(
    CASE 
      WHEN file_name LIKE '\\%' THEN substr(file_name, 2) 
      ELSE file_name 
    END, '^[.]|[.]$', 'c');

Answer 2

在Postgres中带有负参数的

right()很少使用。但是Oracle中的等效项是substr(x, 2)，因此一种方法是：

SELECT *
FROM file 
WHERE file_name IS NOT NULL AND
      REGEXP_LIKE(CASE WHEN file_name LIKE '\\%' THEN substr(file_name, 2) 
                       ELSE file_name 
                  END), '^[.]|[.]$');

但是，我将在两个数据库中使用单个正则表达式来做到这一点：

WHERE REGEXP_LIKE(file_name, '^(\\)?[.]|[.]$');

在进行这种类型的正则表达式匹配时，使用case没有优势。与NULL的比较只是多余的。

How to convert postgreSQL code to Oracle SQL

2 个答案: