在string_agg函数中,可以通过WITHIN GROUP (ORDER BY sort_expression)子句来指定连接前字符串的排序方式。这个子句允许你按照指定的列或表达式对字符串进行排序,然后再进行连接。 4. 提供一个使用string_agg函数并带有排序功能的示例 假设我们有一个名为employees的表,其中包含以下列: department_id:部门ID employee_...
s.insert(0, "sort "); cout << s << endl; } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 3. erase 设计有点冗余,其实大家记住第一种用法就基本够用了。 缺省值:npos 如果第二个参数不给,默认是整型的最大值。如果长度超出剩余字符的长度,就从pos位置开...
A list of non-constantexpressionsthat can be used for sorting results. Only one<order_by_expression_list>is allowed per query. The default sort order is ascending. Return types Return type depends on first argument (expression). If input argument is string type (nvarchar,varchar), the result...
string_agg(expression,delimiter) string_agg函数能将结果集某个字段的所有行连接成字符串,并以delimiter分隔符分隔,expression表示要处理的字符类型数据。 create table t1(id1 int, id2 varchar(64)); insert into t1 values(1,’nanjing’),(1,’suzhou’),(2,’xingtai’),(2,’shijiazhuang’); select ...
PostgreSQL ARRAY_AGG()函数是一个聚合函数,它接受一组值并返回一个数组,其中将输入集中的每个值分配给该数组的元素。 1 用法: ARRAY_AGG(expression [ORDER BY [sort_expression {ASC | DESC}], [...]) ORDER BY子句是自愿性子句。它指定集合中要处理的行的顺序,从而确定结果数组中元素的顺序。它通常与GRO...
您可以使用RETURN TABLE(columns)执行如下操作：string_agg()函数返回text，因此返回的列应为TEXT而不是...
Note this may add a little execution time because of the additional sort operator, depending on whether there’s a supporting index. STRING_AGG() As I update my old answers, which should still work on the version that was relevant at the time of the question, the final snippet above (wit...
A list of non-constantexpressionsthat can be used for sorting results. Only oneorder_by_expressionis allowed per query. The default sort order is ascending. Return Types Return type depends on first argument (expression). If input argument is string type (NVARCHAR,VARCHAR), result type will be...
A list of non-constantexpressionsthat can be used for sorting results. Only oneorder_by_expressionis allowed per query. The default sort order is ascending. Return Types Return type depends on first argument (expression). If input argument is string type (NVARCHAR,VARCHAR), result type will be...
1. Sort the Result with the STRING_AGG Function in SQL We can present the concatenated string values in a specific order by sorting the result of the STRING_AGG function. This feature becomes especially valuable when we want to display the data in an organized and meaningful manner. Using th...