请教

Question

mysql> select date(end_date),sum(charge) from table group by date(end_date) with rollup;
+----------------------+------------------+
| date(end_date) | sum(charge) |
+----------------------+------------------+
| 2010-11-01           |                7 | 
| 2010-11-02           |                4 | 
| NULL                 |               11 | 
+----------------------+------------------+如何让NULL显示成自己想要的文字：total

Answer 1

select COALESCE(date(end_date),'total'),sum(charge) from table group by date(end_date) with rollup;

Answer 2

mysql> select COALESCE(date(end_date),'total'),sum(charge) from table group by date(end_date) with rollup;
+----------------------------------------+------------------+
| COALESCE(date(end_date),'total') | sum(charge) |
+----------------------------------------+------------------+
| 2010-11-01                             |                7 | 
| 2010-11-02                             |                4 | 
| 2010-11-02                             |               11 | 
+----------------------------------------+------------------+不对

Answer 3

select if(date(end_date)<=>null,'total',date(end_date)),sum(charge) from table group by date(end_date) with rollup;

Answer 4

不会吧，示例
SELECT COALESCE(title,'total'),SUM(hotelid) FROM gg GROUP BY title WITH rollupCOALESCE(title,'total') sum(hotelid)
井冈山大酒店 1
南昌春天大酒店 2
南昌富豪酒店 3
total 6

Answer 5

MySQL 5.1.11-beta-log 
还是不对，难道是我数据库有问题？
还显示原来的。二位的都试了

Answer 6

SELECT VERSION()
version()
5.1.31-community

Answer 7

select IFNULL(date(end_date),'total') AS total,sum(charge) from table group by date(end_date) with rollup;