SQLite选择两列作为Null

Question

如果其中一列中有Null，我如何组合这两列？

SELECT (column1 || " " || column2) AS expr1 FROM your_table;

我希望输出为：

Answer 1

SELECT (COALESCE(column1,'') || " " || COALESCE(column2, '')) AS expr1 FROM your_table;