select
Selects some values and discards the rest.
Description
This operator keeps only the provided fields and drops the rest.
field
The field to keep. If it does not exist, it's given the value null
and a
warning is emitted.
assignment
An assignment of the form <field>=<expr>
.
Examples
Keep a
and introduce y
with the value of b
:
A more complex example with expressions and selection through records: