How to import tables with missing values?
You can have columns missing for the whole table. Tell COPY (or the psql wrapper \copy) to only fill those columns appending a column list to the table, for instance:
\copy coaches (coachid, yr_order, firstname)FROM '/Users/.../coaches_data.csv' (FORMAT csv, HEADER, DELIMITER ',');Missing values are filled in with column defaults. Per documentation:
If there are any columns in the table that are not in the column list,
COPY FROMwill insert the default values for those columns.
But you cannot have values missing for just some rows. That's not possible. The text representation of NULL can be used (overruling respective column defaults).
It's all in the manual, really:
ERROR: missing data for column "year" CONTEXT: COPY coaches, line 1: ""coachid";"year";"yr_order";"firstname";"lastname";"season_win";"season_loss";"playoff_win";"playoff..."
This type of error is also the result of a Table-mismatch. The table you are importing the text file into either has more columns or less columns than the text file has.