exec
The select statement always generates a table, even if only one column is selected. To generate a scalar or a vector from one column, use the exec statement.
When used with pivot by, exec generates a matrix. For details please refer to pivot by.
Examples
$ 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 |
$ x = select count(price) from t1;
$ x;
count_price |
---|
9 |
$ typestr x;
TABLE
$ y = exec count(price) from t1;
$ y;
9
$ typestr y;
INT
$ x = select price from t1;
$ x;
price |
---|
49.6 |
29.46 |
29.52 |
30.02 |
174.97 |
175.23 |
50.76 |
50.32 |
51.29 |
$ typestr x;
TABLE
$ y = exec price from t1;
$ y;
[49.6,29.46,29.52,30.02,174.97,175.23,50.76,50.32,51.29]
$ typestr y;
FAST DOUBLE VECTOR
If we use the exec statement to select more than one column, the exec statement is identical as the select statement.
$ y = exec price, qty from t1;
$ y;
price |
qty |
---|---|
49.6 |
2200 |
29.46 |
1900 |
29.52 |
2100 |
30.02 |
3200 |
174.97 |
6800 |
175.23 |
5400 |
50.76 |
1300 |
50.32 |
2500 |
51.29 |
8800 |
$ typestr y;
TABLE