4.71 null - NULL Value

Format: nulln(),nulls(),nulld(),nullt(),nullb()

Return NULL value for corresponding types. It can be used to return NULL value in conjunction with the if function.

Example

Example 1: Basic Example

Print NULL values to column rsl.

$ more dat1.csv
id
1
2
3
$ mcal c='nulls()' a=rsl i=dat1.csv o=rsl1.csv
#END# kgcal a=rsl c=nulls() i=dat1.csv o=rsl1.csv
$ more rsl1.csv
id,rsl
1,
2,
3,

Example 2: Use of if statement

Use nulln() function to match the value specified in the second parameter.

$ mcal c='if(${id}==1,1,nulln())' a=rsl i=dat1.csv o=rsl2.csv
#END# kgcal a=rsl c=if(${id}==1,1,nulln()) i=dat1.csv o=rsl2.csv
$ more rsl2.csv
id,rsl
1,1
2,
3,

Example 3: Equivalent to isnull function

$ mcal c='if(${val}==nulln(),"null","notNull")' a=rsl i=dat2.csv o=rsl3.csv
#END# kgcal a=rsl c=if(${val}==nulln(),"null","notNull") i=dat2.csv o=rsl3.csv
$ more rsl3.csv
id,val,rsl
1,a,
2,,
3,b,