When joining strings in redshift we can use these options:
- The concatenation operator
- The concat() function
The concatenation operator
Syntax: Select <column containing string1> || <column containing string2>
You can add an extra || <column containing string3> and more to concatenate multiple strings
The concat() function
Syntax: Select concat(<string1>,<string2>)
You can concat multiple strings by nesting the concat:
Select concat(<string1>, concat(<string2>,<string3>))
In all instance when there’s a null in any of the columns the resulting expression will be a null. To specify a different output use the nvl expression.
Syntax: Select concat(<column1>, nvl(column2,<default value>))