The likely result is that each input line would be interpreted as a single field. For example, many programs can export data in comma-separated values CSV format, such that lines have fields separated by commas and enclosed within double quotation marks, with an initial line of column names.
Any of the field- or line-handling options can specify an empty string ''. An example of such output using a comma as the field delimiter is shown here:. For example, the preceding output just shown would appear as follows if the escape character is empty.
Observe that the second field in the fourth line contains a comma following the quote, which erroneously appears to terminate the field:. Some two-character sequences that are exceptions, where the first character is the escape character. The rules for NULL handling are described later in this section. 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. With fixed-row format, no delimiters are used between fields but you can still have a line terminator.
Instead, column values are read and written using a field width wide enough to hold all values in the field. If a line does not contain all fields, the rest of the columns are set to their default values. If you do not have a line terminator, you should set this to ''. In this case, the text file must contain all fields for each row. Fixed-row format also affects handling of NULL values, as described later.
Fixed-size format does not work if you are using a multibyte character set. 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. The following example loads all columns of the persondata table:. If you want to load only some of a table's columns, specify a column list:.
You must also specify a column list if the order of the fields in the input file differs from the order of the columns in the table. Otherwise, MySQL cannot tell how to match input fields with table columns. With user variables, the SET clause enables you to perform preprocessing transformations on their values before assigning the result to columns. User variables in the SET clause can be used in several ways. The following example uses the first input column directly for the value of t1.
The SET clause can be used to supply values not derived from the input file. The following statement sets column3 to the current date and time:. You can also discard an input value by assigning it to a user variable and not assigning the variable to any table column:. Assignments in the SET clause should have only column names on the left hand side of assignment operators. You can use subqueries in the right hand side of SET assignments. A subquery that returns a value to be assigned to a column may be a scalar subquery only.
Also, you cannot use a subquery to select from the table that is being loaded. User variables cannot be used when loading data with fixed-row format because user variables do not have a display width.
Then the resulting row is inserted into the table. Interpretation of field values and assignment to table columns depends on these factors:. The mode can be nonstrictive, or restrictive in various ways.
Errors terminate the load operation. In particular, either modifier if specified overrides a restrictive SQL mode. Errors become warnings and the load operation continues. A value that is out of range for the column data type results in an error. Invalid values produce errors.
For example, a value such as 'x' for a numeric column results in an error, not conversion to 0. If an input line has too many fields, the extra fields are ignored and the number of warnings is incremented.
If an input line has too few fields, the columns for which input fields are missing are assigned their default values.
Default value assignment is described in Section Implicit default values are described in Section A value such as 'x' for a numeric column results in conversion to 0. An out-of-range numeric or temporal value is clipped to the closest endpoint of the range for the column data type. How can we validate if CSV file have proper datatype for each column because by default it ignores invalid datatype. Sorry to disturb on such an old answer. It's very convincing but how can I skip some field. Let's say my table has projectId, surveyId and dateTime, how can I skip "views" field?
MD Danish Ansari, Sorry to answer an old question, but you can specify the table columns. They should appear at the end. Nashir Uddin Md. Nashir Uddin 5 5 silver badges 17 17 bronze badges.
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The MySQL server is running with the --secure-file-priv option so it cannot execute this statement This worked for me on windows 8.
Edited my. Carlos Garcia Carlos Garcia 1 1 gold badge 5 5 silver badges 29 29 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Making Agile work for data science. If not, change the ownership to mysql appropriately. The value of all other fields are NULL. In the following example, the input text file has the text field values enclosed by double-quotes.
The above command will upload the records properly as shown below by the mysql select command :. The records are also not loaded properly because there is a comma in the value of one of the fields. You can also use a different escape character as shown below. Please note that some of the characters cannot be used as escape character. You can also have some prefix to the records in your input text file which can be ignored during the upload. For example, in the following employee6.
You can upload only these records by ignoring the line prefix. This is helpful to selectively upload only the records that has certain prefix. In the following input text file, the first line is the header line, which has the name of the columns. During upload, we want to ignore the 1st header lien from the employee7.
As you see from the following output, even though the input file has 6 lines, it ignored the 1st line which is header line and uploaded the remaining 5 lines. In the following example, we have values only for three fields.
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