SELECT (DBMS_LOB.getlength(your_column_name))/1024/1024 AS SizeMB FROM your_table
Here is what the above code is Doing:
1. First, we’re selecting the column name that we want to get the size of.
2. Then, we’re using the DBMS_LOB.getlength function to get the length of the column.
3. Then, we’re dividing the length by 1024 to get the size in KB.
4. Then, we’re dividing the size in KB by 1024 to get the size in MB.
5. Finally, we’re giving the size in MB an alias of SizeMB.