How to Determine Varchar Field Size in a Single SQL Statement

When working with VARCHAR fields, it's often necessary to know their size. This is especially useful for future-proofing queries and ensuring consistent functionality. One efficient way to retrieve the size of a VARCHAR field in a single SQL statement is by leveraging the information_schema table.

SOLUTION

SELECT column_name, data_type, character_maximum_length
FROM information_schema.columns
WHERE table_name = 'myTable';

This query retrieves information about the columns in a specified table. The character_maximum_length column provides the size of the VARCHAR field in characters.

EXAMPLE

Assuming you have a table called myTable with a VARCHAR field named Remarks with a maximum length of 1000 characters, the query will return the following result:

| column_name | data_type | character_maximum_length |
| ------------ | ---------- | ------------------------- |
| Remarks      | VARCHAR    | 1000                      |

By executing this simple query, you can easily determine the size of a VARCHAR field, regardless of its actual length or any changes made to it in the future.