^ Coalesce¶
Merge keyed tables ignoring nulls
x^y ^[x;y]Where x and y are keyed tables, returns them merged.
With no nulls in y, the result is the same as for Join.
q)kt1:([k:1 2 3] c1:10 20 30;c2:`a`b`c)
q)kt2:([k:3 4 5] c1:300 400 500;c2:`cc`dd`ee)
q)kt1^kt2
k| c1 c2
-| ------
1| 10 a
2| 20 b
3| 300 cc
4| 400 dd
5| 500 ee
q)(kt1^kt2) ~ kt1,kt2
1b
^ Fill where x and y are lists or dictionaries
When y has null column values, the column values of x are updated only with non-null values of y.
q)kt3:([k:2 3] c1:0N 3000;c2:`bbb`)
q)kt3
k| c1 c2
-| --------
2| bbb
3| 3000
q)kt1,kt3
k| c1 c2
-| --------
1| 10 a
2| bbb
3| 3000
q)kt1^kt3
k| c1 c2
-| --------
1| 10 a
2| 20 bbb
3| 3000 cThe performance of Coalesce is slower than that of Join since each column value of y must be checked for null.