How to merge columns into one field in SQL?

2 years ago
Olivia Parker
2 minutes

In SQL, you can use aggregate functions and the GROUP BY clause to transform multiple columns into a single field.

Assuming we have a table named “table_name” with two columns, “col1” and “col2”, we now want to merge these two columns into one field.

Here are some commonly used methods:

  1. Use the CONCAT function:
SELECT CONCAT(col1, col2) AS merged_column
FROM table_name;
  1. Utilize the “+” operator (only applicable to databases that support string concatenation) :
SELECT col1 + col2 AS merged_column
FROM table_name;
  1. Utilize the string concatenation function (the function name may vary depending on the database).
  1. MySQL and MariaDB: Utilizing the CONCAT function.
SELECT CONCAT(col1, col2) AS merged_column
FROM table_name;
  1. Oracle: Using the “||” operator.
SELECT col1 || col2 AS merged_column
FROM table_name;
  1. SQL Server: using the “+” operator
SELECT col1 + col2 AS merged_column
FROM table_name;

Please note that some of the methods in the above approach may need to be appropriately modified based on the type of database you are using.

You can use the GROUP_CONCAT function (available in MySQL and MariaDB) to merge multiple rows into a single field.

SELECT GROUP_CONCAT(col1) AS merged_column
FROM table_name;

Here are some common methods of combining multiple columns into one field, the specific method will depend on the type of database you are using and your specific needs.

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