any/all

New in version 1.30.21.

any 和 all 关键字用于 where 或 having 子句。

$ where/having col optr any(sub_query)
$ where/having col optr all(sub_query)

其中 optr 是比较运算符,sub_query 是一个 SQL 查询或者向量。

any/all 关键字将比较运算符前的操作数(通常是某列的值)与子查询结果集或向量中的值一一比较:

  • any:若存在满足条件的子查询结果或向量值,则返回 true,否则为 false。

  • all:若所有子查询结果或向量值都满足比较条件,则返回 true,否则返回 false。

注:

  • “= any“ 等价于 “in”;”= all” 等价于 “!= any”;

  • SQL 的 any / all 谓词和内置函数 any / all 功能类似但不同。前者用于值比较,后者用于判断布尔值。

下面以两个语句来说明区别:

SQL 中的 any 谓词:

$ x > any([n1,n2,n3])

内置 any 函数:

$ any([x>n1, x>n2, x>n3])

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);
$ t2 = table(`C`MS`IBM as sym, 1 0 1 as flag)

$ select * from t1 where sym = any(select sym from t2 where flag=1)
timestamp sym qty price
09:34:07 C 2,200 49.6
09:32:47 IBM 6,800 174.97
09:35:26 IBM 5,400 175.23
09:34:16 C 1,300 50.76
09:34:26 C 2,500 50.32
09:38:12 C 8,800 51.29
$ select * from t1 where sym != all(select sym from t2 where flag = 1)
timestamp sym qty price
09:36:42 MS 1,900 29.46
09:36:51 MS 2,100 29.52
09:36:59 MS 3,200 30.02
$ t3 = select wavg(price, qty) as wavg from t1 group by sym
$ select * from t1 where price >= all(select wavg from t3)
timestamp sym qty price
09:35:26 IBM 5,400 175.23
$ select * from t1 where price >= any(select wavg from t3)
timestamp sym qty price
09:34:07 C 2,200 49.6
09:36:59 MS 3,200 30.02
09:32:47 IBM 6,800 174.97
09:35:26 IBM 5,400 175.23
09:34:16 C 1,300 50.76
09:34:26 C 2,500 50.32
09:38:12 C 8,800 51.29