2列的合并内容

Question

How do I join the content of two columns for the resulting column below:

Group:         Family:
polychaete     spionidae
gastropod      rossoidae
foraminifera   rotaliidae
polychaete     magelonidae

result needed:

Taxa:
polychaete_spionidae
gastropod_rossoidae
foraminifera_rotaliidae
polychaete_magelonidae

Answer 1

In ANSI SQL, we can use the concatenation operator || :

SELECT "Group" || '_' || Family AS Taxa
FROM yourTable;

This would vary depending on the database. For instance, SQL Server uses + as the concatenation operator. Some databases have formal concatenation functions.

By the way, you should avoid naming your columns using SQL keywords like Group .