Importing Non-ISO Date Values
Problem
Date values
to be imported are not in the ISO (CCYY-MM-DD
) format that
MySQL expects.
Solution
Use an external utility to convert the dates to ISO format
before importing the data into MySQL (cvt_date.pl is useful here). Or use LOAD
DATA
’s capability for preprocessing input
data before it gets loaded into the database.
Discussion
Suppose that you have a table that contains three columns,
name
, date
, and value
, where date
is a DATE
column requiring values in ISO format
(CCYY-MM-DD
). Suppose also that you’re
given a datafile newdata.txt to
be imported into the table, but its contents look like this:
name1 01/01/99 38 name2 12/31/00 40 name3 02/28/01 42 name4 01/02/03 44
Here the dates are in MM/DD/YY
format
and must be converted to ISO format to be stored as DATE
values in MySQL. One way to do this is
to run the file through the cvt_date.pl script shown earlier in the
chapter:
%cvt_date.pl --iformat=us --add-century newdata.txt > tmp.txt
You can then load the tmp.txt file into the table. This task also
can be accomplished entirely in MySQL with no external utilities by
using SQL to perform the reformatting operation. As discussed in Preprocessing Input Values Before Inserting Them, LOAD
DATA
can preprocess input values before inserting them. Applying that
capability to the present problem, the date-rewriting LOAD
DATA
statement looks like this, using the STR_TO_DATE()
function (Changing MySQL’s Date Format) to interpret the input
dates:
mysql>LOAD DATA ...
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