CODEWITHSUNDEEP
mysql
greatak
greatak

Reputation: 43

Using BLOB in where clause in MySQL

I am working on an application that will need to do some verification on data by checking fingerprints stored in a MySQL database.It was proposed to use proprietary software such as 'AFIS'..but i am wondering if the check can be done by using the BLOB column in the "where" clause of a select statement to filter the data. Is this possible?

The code i have in mind is something like this:

     Select id from mytable
     where image not in
    (select image from other table)

With the image columns being of blob datatype

Upvotes: 4

Views: 2164

Answers (1)

Sudhir Bastakoti
Sudhir Bastakoti

Reputation: 100195

Do you mean something like this:


SELECT * FROM yourTable WHERE CHAR_LENGTH(your_blob_field) > 0

char_length() works on a blob column type... if that is anything but 0 then you know you've got something in there.

Upvotes: 3

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