I have a two column csv file that has only numeric data. I create a table in Postgre with the columns as numeric. I successfully use the import wizard, but it gives all my values in the postgre table as null. Not sure why.
Related
I am creating an Athena external table on a CSV that I generated from my PostgreSQL database.
The csv contains a columns that has a jsonb datatype.
If possible, I want to exclude this column from the table created in Athena, or kindly suggest a way to include this datatype.
Hi I am trying to import data to a postgresql table from a csv file, so I'd like to know how do I exlude the first column since it is an identity column that increments when data is inserted?
Error I get is here
If you are using some script to add or modify data, then you should just skip the variable on the script (e.g. does not write then on the insert statement), but on doing so you should modify your csv to delete the insert column(the data, if any, and the separator, usually a comma) since the number of variables are now different.
Looking at your print I suppose you are using pgadmin or some simmilar GUI, on the case of pgadmin if you click on the column and select the import\export data... option, you will open a windows where you should select "import" and then, on the upper windows menu, click on "columns" and exclude the "ID" or any other auto-increment, this slution also needs you to remove the csv column as well.
I have a raw data loaded into my hive tables with all the columns as strings by default. Now I need to change the datatypes of hive tables to export to SQLServer.
When Typecasting the hive columns the empty fields returns 'NULL', tried loading the hive tables into dataframe and typecast the columns, but still dataframe also returning 'null' for empty fields. SQLserver couldn't recognize such values.
Can anyone suggest a solution to avoid the 'null' values in display when I get data from hive or dataframes.
If you want to change the data type only because you want to have that particular format in exported data, consider using writing to a directory as per your requirement and then export using sqoop/any other tool.
INSERT OVERWRITE DIRECTORY '<HDFS path>'
Row format delimited
Fields terminated by '<delimiter>'
SELECT
a,
b
From
table_name
Where <condition>;
While exporting, if you have null values consider using these arguments in your sqoop command
--null-string "\\N" --null-non-string "\\N"
Hope this helps you
I am using PostgreSQL 9.6. I have created a table with create query.
But when i checked in left panel of pgAdmin, under table i found more six columns named tableid,cmax,xmax,cmin,xmin and ctid.
When i searched about this, I found that these are OIDs column and does not affect to data on other columns.
I have to import data into this table. So after selecting table, from right click i got option for import/Export. So from that i am importing .csv file.
But when i tried to import the data in table, i am getting error like,
ERROR: column "tableoid" of relation "account" does not exist
Please suggest me how to eliminate these OID columns from table.
You must be missing some column that is present in the csv named "tableoid".
In this case ,TABLE according to the import file must be created first. IF there is no prior table , it wont work. This may help.
http://www.postgresqltutorial.com/import-csv-file-into-posgresql-table/
I have a CSV file file.csv.
In Postgres, I have made a table named grants:
CREATE TABLE grants
(
)
WITH (
OIDS=FALSE
);
ALTER TABLE grants
OWNER TO postgres;
I want to import file.csv data without having to specify columns in Postgres.
But if I run COPY grants FROM '/PATH/TO/grants.csv' CSV HEADER;, I get this error: ERROR: extra data after last expected column.
How do I import the CSV data without having to specify columns and types?
The error is normal.
You created a table with no column. The COPY command try to import data into the table with the good structure.
So you have to create the table corresponding to your csv file before execute the COPY command.
I discovered pgfutter :
"Import CSV and JSON into PostgreSQL the easy way. This small tool abstract all the hassles and swearing you normally have to deal with when you just want to dump some data into the database"
Perhaps a solution ...
The best method for me was to convert the csv to dataframe and then follow
https://github.com/sp-anna-jones/data_science/wiki/Importing-pandas-dataframe-to-postgres
No, it is not possible using the COPY command
If a list of columns is specified, COPY will only copy the data in the
specified columns to or from the file. If there are any columns in the
table that are not in the column list, COPY FROM will insert the
default values for those columns.
COPY does not create columns for you.