I tried to import data from csv to mysql with wizard, rows contain null values are not included in the imported table.
How to fix it?
You need to handle the NULL in you csv file, as described on MySQL manual :
Handling of NULL values varies according to the FIELDS and LINES options in use:
For the default FIELDS and LINES values, NULL is written as a field value of \N for output, and a field value of \N is read as NULL for input (assuming that the ESCAPED BY character is ).
If FIELDS ENCLOSED BY is not empty, a field containing the literal word NULL as its value is read as a NULL value. This differs from the word NULL enclosed within FIELDS ENCLOSED BY characters, which is read as the string 'NULL'.
If FIELDS ESCAPED BY is empty, NULL is written as the word NULL.
With fixed-row format (which is used when FIELDS TERMINATED BY and FIELDS ENCLOSED BY are both empty), NULL is written as an empty string. This causes both NULL values and empty strings in the table to be indistinguishable when written to the file because both are written as empty strings. If you need to be able to tell the two apart when reading the file back in, you should not use fixed-row format.
So you if there is NULL in csv data, replace it by \N.
E.g.: replace
1, foo, NULL, bar
by :
1, foo, \N, bar
Related
Iam getting the below error when I try to load CSV From my system to Snowflake table:
Unable to copy files into table.
Numeric value '"4' is not recognized File '#EMPP/ui1591621834308/snow.csv', line 2, character 25 Row 1, column "EMPP"["SALARY":5] If you would like to continue loading when an error is encountered, use other values such as 'SKIP_FILE' or 'CONTINUE' for the ON_ERROR option. For more information on loading options, please run 'info loading_data' in a SQL client.
You appear to be loading your CSV with the file format option of FIELD_OPTIONALLY_ENCLOSED_BY='"' specified.
This option will allow reading any fields properly quoted with the " character, and even support such fields carrying the delimiter character as well as the " character if properly escaped. Some examples that could be considered valid:
CSV FORM | ACTUAL DATA
------------------------
abc | abc
"abc" | abc
"a,bc" | a,bc
"a,""bc""" | a,"bc"
In particular, notice that the final example follows the specified rule:
When a field contains this character, escape it using the same character. For example, if the value is the double quote character and a field contains the string A "B" C, escape the double quotes as follows:
A ""B"" C
If your CSV file carries quote marks within the data but is not necessarily quoting the fields (and delimiters and newlines do not appear within data fields), you can remove the FIELD_OPTIONALLY_ENCLOSED_BY option from your file format definition and just read the file at the delimited (,) fields.
If your CSV does use quoting, ensure that whatever is producing the CSV files is using a valid CSV format writer and not simple string munging, and recreate it with the quotes properly escaped. If the above data example is to be considered valid in quoted form, it must instead appear within the file as "4" or 4.
The error message is saying that you have a value in your file that contains a "4 which is being added into a table that has a number field for that value. Since that isn't a number, it fails. This appears to be happening in your very first row of your file, so you could open it up and take a look at the value. If its just one record, you can add the ON_ERROR = 'CONTINUE' to your command, so that it skips it and moves on.
While importing a tab-separated-values (TSV) file, I find that there are two cases where mysql injects double quotes that I would like to disable.
Case 1: When the field value is empty/blank (zero characters) - instead of a NULL, a "" gets inserted. I prefer it be just a NULL.
Case 2: When a double quote is already in the string (i.e. 2" Square), it replaces the occurrence of the double quote with two double quotes and it also wraps the entire string in double quotes. Example: 2" Square gets inserted as "2"" Square". I want it to be just 2" Square, just as it is in the report.tsv file.
The current SQL I am using is (report-columns is a list of columns each with the definition VARCHAR(25) DEFAULT NULL)
LOAD DATA LOCAL INFILE 'report.tsv'
INTO TABLE properties
IGNORE 1 LINES (report-columns)
I tried adding FIELDS ESCAPED BY '' but this didn't change the results.
I prefer a plan to be able to just disable this from happening in the first place in the same query that loads the file, but if that is not possible a backup plan would be to execute a cleanup query for all report-columns to be run immediately after import to address both cases 1 and 2 above.
Ideas on either plan?
Update
After further investigation into this I determined that it was not mysql's loading of the data that was causing case 2, rather it was a clean script just before the load. The answer for using SET and NULLIF in the same query with the LOAD DATA LOCAL INFILE statement has resolved case 1 nicely without needing a second query cleanup.
If you want a NULL to be inserted, you can use a literal \N in your source text file, or the word NULL, depending on some of your options. This is documented in the manual for LOAD DATA INFILE: https://dev.mysql.com/doc/refman/5.7/en/load-data.html
Look for the phrase "Handling of NULL values varies according to the FIELDS and LINES options in use" and read what follows (I'm not going to copy the manual into this Stack Overflow answer).
Another option is to use an expression to modify the value on import if it's an empty string:
LOAD DATA LOCAL INFILE 'report.tsv'
INTO TABLE properties
IGNORE 1 LINES (report-columns)
SET some_col = NULLIF(some_col, '');
I'm not sure what to recommend for the second case, when you have double-quotes in your input text data. I tried this, and it worked fine for me. I was able to import the string 2" square.
It could be complicated if you use LOAD DATA INFILE with the ENCLOSED BY '"' option. You might want to enclose fields by some different character that doesn't appear in the text.
I am migrating a MySQL 5.5 physical host database to a MySQL 5.6 AWS Aurora database. I noticed that when data is written to a file using INTO OUTFILE, 5.5 writes NULL value as '\N' and empty string as ''. However, 5.6 writes both empty string and NULL as ''.
Query
SELECT * FROM $databasename.$tablename INTO OUTFILE $filename CHARACTER SET utf8 FIELDS ESCAPED BY '\\\\' TERMINATED BY $delimiter;
I found official documents about this:
https://dev.mysql.com/doc/refman/5.6/en/load-data.html
With fixed-row format (which is used when FIELDS TERMINATED BY and
FIELDS ENCLOSED BY are both empty), NULL is written as an empty
string. This causes both NULL values and empty strings in the table to
be indistinguishable when written to the file because both are written
as empty strings. If you need to be able to tell the two apart when
reading the file back in, you should not use fixed-row format.
How do I export NULL as '\N'?
How do I export NULL as '\N'?
First of all that's strange and why you want to do that? But if for some reason you want to export it that way then you will have to change your query from select * to using a CASE expression like
select
case when col1 is null then '\\N' else col1 end as col1,
...
from $databasename.$tablename....
As commented you can as well use IFNULL() function or COALESCE() function for the same purpose.
Data:
1|\N|"First\Line"
2|\N|"Second\Line"
3|100|\N
\N represents NULL in MYSQL & MariaDB.
I'm trying to load above data using LOAD DATA LOCAL INFILE method into a table named ID_OPR.
Table structure:
CREATE TABLE ID_OPR (
idnt decimal(4),
age decimal(3),
comment varchar(100)
);
My code looks like below:
LOAD DATA LOCAL INFILE <DATA FILE LOCATION> INTO TABLE <TABLE_NAME> FIELDS TERMINATED BY '|' ESCAPED BY '' OPTIONALLY ENCLOSED BY '\"' LINES TERMINATED BY '\n';
Problem with this code is it aborts with error Incorrect decimal value: '\\N' For column <Column name>.
Question:
How to load this data with NULL values in second decimal column and also without loosing \(Backslash) from third string column?
I'm trying this is MariaDB which is similar to Mysql in most case.
Update:
The error i have mentioned appears like a warning and the data is actually getting loaded into table. But the catch here is with the text data.
For example: Incase of the third record above it is being loaded as \N itself into string column. But i want it to be NULL.
Is there any way to make the software to recognize this null value? Something like decode in oracle?
You can't have it both ways - either \ is an escape character or it is not. From MySQL docs:
If the FIELDS ESCAPED BY character is empty, no characters are escaped and NULL is output as NULL, not \N. It is probably not a good idea to specify an empty escape character, particularly if field values in your data contain any of the characters in the list just given.
So, I'd suggest a consistently formatted input file, however that was generated:
use \\ if you want to keep the backslash in the strings
make \ an escape character in your load command
OR
make strings always, not optionally, enclosed in quotes
leave escape character empty, as is
use NULL for nulls, not \N
BTW, this also explains the warnings you were experiencing loading \N in your decimal field.
Deal with nulls with blanks. that should fix it.
1||"First\Line"
2||"Second\Line"
3|100|
Thats how nulls are handled on CSVs and TSVs. And don't expect decimal datatype to go null as it stays 0, use int or bigint instead if needed. You should forget about "ESCAPED BY"; as long as string data is enclosed by "" that deals with the escaping problem.
we need three text file & 1 batch file for Load Data:
Suppose your file location 'D:\loaddata'
Your text file 'D:\loaddata\abc.txt'
1. D:\loaddata\abc.bad -- empty
2. D:\loaddata\abc.log -- empty
3. D:\loaddata\abc.ctl
a. Write Code Below for no separator
OPTIONS ( SKIP=1, DIRECT=TRUE, ERRORS=10000000, ROWS=5000000)
load data
infile 'D:\loaddata\abc.txt'
TRUNCATE
into table Your_table
(
a_column POSITION (1:7) char,
b_column POSITION (8:10) char,
c_column POSITION (11:12) char,
d_column POSITION (13:13) char,
f_column POSITION (14:20) char
)
b. Write Code Below for coma separator
OPTIONS ( SKIP=1, DIRECT=TRUE, ERRORS=10000000, ROWS=5000000)
load data
infile 'D:\loaddata\abc.txt'
TRUNCATE
into table Your_table
FIELDS TERMINATED BY ","
TRAILING NULLCOLS
(a_column,
b_column,
c_column,
d_column,
e_column,
f_column
)
4.D:\loaddata\abc.bat "Write Code Below"
sqlldr db_user/db_passward#your_tns control=D:\loaddata\abc.ctl log=D:\loaddata\abc.log
After double click "D:\loaddata\abc.bat" file you data will be load desire oracle table. if anything wrong check you "D:\loaddata\abc.bad" and "D:\loaddata\abc.log" file
I'm trying to import a CSV file into a MySQL 5.1 DB using phpMyAdmin. The file includes several date columns which may contain NULL values. According to the manual, NULL should be written as \N. However, after an otherwise successful import, \N appears as 0000-00-00 in the date columns (as opposed to NULL). How do I get NULLs imported?
Options set:
line separator ,
fields enclosed by ",
fields escaped by \,
lines terminated by auto.
phpMyAdmin distinguishes two CSV import formats: CSV and CSV with LOAD DATA. The latter option actually accepts \N as described in the manual.
If columns are enclosed by a character (as it is the case), NULLs may also be imported using the former method (no LOAD DATA) by setting a value to a non-enclosed NULL in the CSV file. This is in accordance with the manual's following statement:
If FIELDS ENCLOSED BY is not empty, a field containing the literal
word NULL as its value is read as a NULL value. This differs from the
word NULL enclosed within FIELDS ENCLOSED BY characters, which is read
as the string 'NULL'.