docs: clarify handling of column lists in COPY TO/FROM

Previously it was unclear how COPY FROM handled cases where not all
columns were specified, or if the order didn't match.

Reported-by: pavlo.golub@gmail.com

Discussion: https://postgr.es/m/157487729344.7213.14245726713444755296@wrigleys.postgresql.org

Backpatch-through: 9.4
This commit is contained in:
Bruce Momjian 2019-12-21 12:44:38 -05:00
parent 1a77ea02dc
commit 7b94a0b389

View File

@ -61,11 +61,11 @@ COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable
</para> </para>
<para> <para>
If a list of columns is specified, <command>COPY</command> will If a column list is specified, <command>COPY TO</command> copies only
only copy the data in the specified columns to or from the file. the data in the specified columns to the file. For <command>COPY
If there are any columns in the table that are not in the column list, FROM</command>, each field in the file is inserted, in order, into the
<command>COPY FROM</command> will insert the default values for specified column. Table columns not specified in the <command>COPY
those columns. FROM</command> column list will receive their default values.
</para> </para>
<para> <para>