SQL中Select语句排序的技巧

在SQL中，可以使用ORDER BY子句对查询结果进行排序。下面是一些常用的技巧：

按单个列排序：SELECT * FROM table_name ORDER BY column_name ASC/DESC;

按多个列排序：SELECT * FROM table_name ORDER BY column1 ASC/DESC, column2 ASC/DESC;

按列的位置排序：SELECT * FROM table_name ORDER BY 2 ASC/DESC;

按多列不同排序方式：SELECT * FROM table_name ORDER BY column1 ASC, column2 DESC;

按字符串排序：SELECT * FROM table_name ORDER BY column_name COLLATE “NOCASE”;

按NULL值排序：SELECT * FROM table_name ORDER BY column_name NULLS FIRST/LAST;

按条件排序：SELECT * FROM table_name ORDER BY CASE WHEN condition1 THEN 1 WHEN condition2 THEN 2 ELSE 3 END;

按表达式结果排序：SELECT * FROM table_name ORDER BY expression_name;