Finding Tables with Specific Column Names in MySQL

MySQL provides an efficient way to search for tables containing specific column names using its built-in INFORMATION_SCHEMA. This tutorial will guide you through the process of finding all tables in a database that have certain columns.

Introduction to INFORMATION_SCHEMA

The INFORMATION_SCHEMA is a virtual database in MySQL that contains metadata about the server, including databases, tables, columns, and more. It provides a standardized way to access this information, making it easier to manage and query your database.

Querying the INFORMATION_SCHEMA

To find all tables with specific column names, you can use the COLUMNS table within the INFORMATION_SCHEMA. This table contains information about each column in the database, including its name, data type, and the table it belongs to.

Here’s an example query that finds all tables with columns named columnA or ColumnB:

SELECT DISTINCT TABLE_NAME 
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME IN ('columnA', 'ColumnB')
  AND TABLE_SCHEMA = 'YourDatabase';

In this query:

• We select the distinct TABLE_NAME from the COLUMNS table to avoid duplicate results.
• The WHERE clause filters the columns based on their names using the IN operator, which allows us to specify multiple column names.
• The AND TABLE_SCHEMA = 'YourDatabase' condition restricts the search to a specific database.

Searching for Columns with Wildcards

If you want to find tables containing columns whose names match a certain pattern, you can use the LIKE operator. For example:

SELECT TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE '%wild%';

In this query:

• The LIKE operator searches for column names that contain the string 'wild'.
• The % wildcard matches any characters before or after the search string.

Tips and Variations

• To find tables with columns whose names start with a certain prefix, use the LIKE operator with a wildcard at the end: COLUMN_NAME LIKE 'prefix%'.
• You can combine multiple conditions using the AND and OR operators to filter the results based on different criteria.
• If you need to search for columns in a specific database, make sure to specify the TABLE_SCHEMA condition.

Older MySQL Versions or NDB Cluster

In older MySQL versions or some MySQL NDB Cluster versions that do not have access to the INFORMATION_SCHEMA, you can dump the table structure using mysqldump and search for the column names manually:

mysqldump -h$host -u$user -p$pass --compact --no-data --all-databases > some_file.sql

You can then use a text editor or tools like AWK or sed to find the column name in the resulting SQL file.

By following this tutorial, you should be able to efficiently find tables with specific column names in your MySQL database using the INFORMATION_SCHEMA.