makeCall

语法

makeCall(F, args...)

参数

F 是一个函数。

args 是 F 需要的参数。

详情

它使用指定参数调用一个函数并生成脚本。高阶函数 call 与 makeCall 的区别是，makeCall 不执行脚本。

例子

在下列例子中，我们创建了 generateReport 函数。它能够以指定格式显示表的某些列。

def generateReport(tbl, colNames, colFormat): sql(sqlColAlias(each(makeCall{format},sqlCol(colNames),colFormat),colNames), tbl).eval();

t = table(1..100 as id, (1..100 + 2018.01.01) as date, rand(100.0, 100) as price, rand(10000, 100) as qty, rand(`A`B`C`D`E`F`G, 100) as city);
t;


id	date	price	qty	city
1	2018.01.02	77.9896	375	A
2	2018.01.03	8.1332	7864	F
3	2018.01.04	56.7185	4912	B
4	2018.01.05	72.4173	534	E
5	2018.01.06	8.2019	31	B
6	2018.01.07	74.7275	4139	A
7	2018.01.08	7.5421	2725	D
8	2018.01.09	59.1689	3095	C
9	2018.01.10	55.8454	5443	D
10	2018.01.11	32.1285	6998	G
...

generateReport(t, ["id", "date","price","qty"], ["0", "MM/dd/yyyy", "0.00", "#,###"]);


id	date	price	qty
1	01/02/2018	77.99	375
2	01/03/2018	8.13	7,864
3	01/04/2018	56.72	4,912
4	01/05/2018	72.42	534
5	01/06/2018	8.20	31
6	1/07/2018	74.73	4,139
7	01/08/2018	7.54	2,725
8	01/09/2018	59.17	3,095
9	01/10/2018	55.85	5,443
10	01/11/2018	32.13	6,988
...

与之等效的 SQL 脚本是：

def generateReportSQL(tbl, colNames, colFormat): sql(sqlColAlias(each(makeCall{format},sqlCol(colNames),colFormat),colNames), tbl)
generateReportSQL(t, ["id", "date","price","qty"], ["0", "MM/dd/yyyy", "0.00", "#,###"]);
# output
< select format(id, "0") as id,format(date, "MM/dd/yyyy") as date,format(price, "0.00") as price,format(qty, "#,###") as qty from t >