Concatenates the elements of one or more one-dimensional arrays using a specified delimiter.

How To Use in Sheets

JOIN(delimiter, value_or_array1, [value_or_array2, ...])

External Links

Google Sheets Join Strings, Text in Cells - CONCATENATE, JOIN, &, JOINTEXT Functions Tutorial

In this tutorial we'll cover how to use Google Sheets Join function, TEXTJOIN function, & operator and CONCATENATE function to join strings (join cells) in Google Sheets.

6Better Sheets Tutorials

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One more function beyond Concatenate and Join that is useful in so many different ways. Concat can be used to quickly create unique columns of data. But watch out for dates!