Substring Select MySQL

Question

My problem is the following:

I got this:

SELECT table_name FROM information_schema.tables WHERE table_schema = 'cr' limit 1;

+------------+
| table_name |
+------------+
| users      |
+------------+

and I want to extract the first letter only:

I am trying:

substring(SELECT table_name FROM information_schema.tables WHERE table_schema = 'cr' limit 1,1,1);

Answer 1

You aren't supposed to use SUBSTRING() on a query, but you can use it on a column, like this:

SELECT SUBSTRING(table_name, 1, 1) FROM information_schema.tables WHERE table_schema = 'cr' limit 1;

You can also use LEFT(table_name, 1) which is a lot more self-explanatory.

Answer 2

SUBSTRING should be applied to the table_name column:

SELECT SUBSTRING(table_name, 1, 1) FROM information_schema.tables WHERE table_schema = 'cr' LIMIT 1;