Is there any way to count null values in a column by using information\_Schema tables? EG:

```
 SELECT table_name, table_rows
 FROM INFORMATION_SCHEMA.TABLES
 WHERE TABLE_SCHEMA ='myschema'
 and table_name='mytable'
 and table_rows is null;

```

Clarifications from comments:

I can not get the number of null values directly from the table as the table is large and not even returning the count of null values, so I thought `information_schema` would be the best option to get count null values from table. But I don't know how to do this. Is there a way? 

I have a table named `cal` and one of its column contains null values. I just need to count the number of those null values. As table is large I cannot get result by using `select count(*) from tablename where column_name is null`.

So I need a query which counts null values from Information\_Schema somehow. 

About the suggestion to add index:

> 
> But can I add an index on a column if `column_type = mediumtext`?
> 
> 
> 

MySQL version 5.1.73 and table is MyISAM.