order by

根据 order by 指定的列，对结果排序。

New in version 1.30.17: order by 支持使用 as 改名前或改名后的字段

New in version 1.30.21: order by 支持 nulls frist/nulls last，语法如下：

$ order by col [asc | desc] [nulls first | nulls last]

asc | desc 指定按升序或降序对数据进行排序。若不指定，则默认为升序。

nulls first | nulls last 指定空值放在排序查询结果的最前面或最后面。注意，指定 nulls first/last 时，必须要指定 asc/desc。

例子

$ sym = `C`MS`MS`MS`IBM`IBM`C`C`C$SYMBOL
$ price= 49.6 29.46 29.52 30.02 174.97 175.23 50.76 50.32 51.29
$ qty = 2200 1900 2100 3200 6800 5400 1300 2500 8800
$ timestamp = [09:34:07,09:36:42,09:36:51,09:36:59,09:32:47,09:35:26,09:34:16,09:34:26,09:38:12]
$ t1 = table(timestamp, sym, qty, price);
$ t1;

timestamp	sym	qty	price
09:34:07	C	2200	49.6
09:36:42	MS	1900	29.46
09:36:51	MS	2100	29.52
09:36:59	MS	3200	30.02
09:32:47	IBM	6800	174.97
09:35:26	IBM	5400	175.23
09:34:16	C	1300	50.76
09:34:26	C	2500	50.32
09:38:12	C	8800	51.29

select * from t1 order by sym, timestamp;

timestamp	sym	qty	price
09:34:07	C	2200	49.6
09:34:16	C	1300	50.76
09:34:26	C	2500	50.32
09:38:12	C	8800	51.29
09:32:47	IBM	6800	174.97
09:35:26	IBM	5400	175.23
09:36:42	MS	1900	29.46
09:36:51	MS	2100	29.52
09:36:59	MS	3200	30.02

可使用”desc”关键字进行降序排序。

select * from t1 where sym in `C`IBM order by sym, timestamp desc;

timestamp	sym	qty	price
09:38:12	C	8800	51.29
09:34:26	C	2500	50.32
09:34:16	C	1300	50.76
09:34:07	C	2200	49.6
09:35:26	IBM	5400	175.23
09:32:47	IBM	6800	174.97

t = table(5 3 NULL NULL 1 6 8 as id, 1 2 3 4 5 6 7 as val)
select * from t order by id asc nulls last

id	val
1	5
3	2
5	1
6	6
8	7
	3
	4

t = table(5 3 NULL NULL 1 6 8 as id, 1 2 3 4 5 6 7 as val)
select * from t order by id asc nulls first

id	val
	3
	4
1	5
3	2
5	1
6	6
8	7