oracle blob 文本搜索 [英] oracle blob text search

问题描述

是否可以使用 sql 语句搜索 blob 文本?我可以选择 * from $table where f1 like '%foo%' 如果 f1 是 varchar，那么 f1 是一个 blob 怎么样?这有什么对应的部分吗?

Is it possible to search through blob text using sql statement? I can do select * from $table where f1 like '%foo%' if the f1 is varchar, how about f1 is a blob? Any counter part for this?

推荐答案

这很有可能而且很容易做到.

This is quite possible and easy to do.

只需将 dbms_lob.instr 与 utl_raw.cast_to_raw 结合使用

Simply use dbms_lob.instr in conjunction with utl_raw.cast_to_raw

因此，在您的情况下，如果 t1 是 BLOB，则选择将如下所示:

So in your case, if t1 is a BLOB the select would look like:

select *
  from table1
 where dbms_lob.instr (t1, -- the blob
                   utl_raw.cast_to_raw ('foo'), -- the search string cast to raw
                   1, -- where to start. i.e. offset
                   1 -- Which occurrance i.e. 1=first
                    ) > 0 -- location of occurrence. Here I don't care.  Just find any
;

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