I have the following select statement, for which the result is sent to a command line parameter:
"SELECT show.file \
FROM show, schedule \
WHERE channel = 1 AND start_time <= UNIX_TIMESTAMP()"
However, if the result returned has spaces in it, it will cause the command to fail. How can I escape out any spaces in the result? Note that this select statement will only ever return one result.
SELECT REPLACE(show.file, " ", "\ ")
FROM show, schedule
WHERE channel = 1 AND start_time <= UNIX_TIMESTAMP()
Should do the trick. If you have another escape character replace \ with the respective one.
See also
http://dev.mysql.com/doc/refman/5.1/de/string-functions.html
If Markus' solution didn't work, try using the 'xargs' command.
xargs YOUR_COMMAND YOUR_QUERY_RESULT_AS_PARAMETER
depending on the command you're gonna use, it may or may not work.
Related
I intend to execute a SQL as following and get the result outputted to terminal:
echo "select * from tbl limit 10" | mysql -hxxx -uxxx -pxxx -Dxxx
there's one field's content having single-quote in it, which is a JSON. I'd like the result being "{\'a\': 1}", yet what it yields is "{'a': 1}".
OUTFILE could not be applied in current scenario. Could anyone help out? Thanks!
I have read the forums to find a solution for my issue but I am stuck with a MySQL error when I use the query.
I want to extract part of a field, everything that is after \\nt4\applications\prod\hde\atn\ in the FILE_NAME column
Here is the query:
SELECT FILE_NAME,
REPLACE (FILE_NAME,'\\nt4\applications\prod\hde\atn\','') as newfilename
from atn_documents
It always return me a
syntax error near ''\
It looks like the string to look into can not contains \ character??
Can anyone drive me?
Thanks
Cedric
Use SUBSTRING_INDEX:
SELECT
SUBSTRING_INDEX(FILE_NAME,
'\\nt4\\applications\\prod\\hde\\atn\\',
-1) AS path
FROM yourTable;
Demo
The above query is a verbatim implementation of your requirement, since it returns only what is after the path of interest. Also note that the immediate reason why your query does not even run is that you need to escape backslashes by doubling them up \\ if you want them as literals.
You have to escape the "\" character in the query. You can add additional "\" to escape it.
e.g.
SELECT FILE_NAME, REPLACE (FILE_NAME,'\\nt4\\applications\\prod\\hde\\atn\\','') as newfilename from atn_documents
I am trying to get a quoted csv output from beeline. My query looks like:
beeline -u 'jdbc:hive2://localhost:10000/' --outputformat=csv2 -e 'set system:disable.quoting.for.sv=false; select 1 as a, 2 as b'
I expect as output
"a","b"
"1","2"
But only get the non-quoted version.
According to the documentation:
The quoting can be disabled by setting the disable.quoting.for.sv system variable to true.
I suppose I am doing something wrong here. How can I set this variable to false? Having it in my query does not seem to do the trick, having it on hive-site.xml neither.
Note: hive 1.2.1 on hdp 2.5.
Quoting fields in csv is only necessary/useful when the field contains a separator or a newline.
So if you try to write 1 2,3, the last value should be quoted: 1,"2,3".
Quoting a field does not mean it should be treated as a string. The "2,3" is still a number (if the , is the decimal separator in this case).
Some csv writers add quotes around every field, which is totally unnecessary and only makes the file larger without any benefit.
The documentation seems to be clear about this too:
If quoting is not disabled, double quotes are added around a value if
it contains special characters (such as the delimiter or double quote
character) or spans multiple lines.
Embedded double quotes are escaped with a preceding double quote.
You can try:
beeline --disableQuotingForSV=true --verbose=true -u 'jdbc:hive2://localhost:10000/' --outputformat=csv2 -e 'select 1 as a, 2 as b'
this will work:
env HADOOP_CLIENT_OPTS="-Ddisable.quoting.for.sv=false" beeline -u 'jdbc:hive2://localhost:10000/' --outputformat=csv2 -e 'select 1 as a, 2 as b'
I use the following construct in a shell script (using dash, but I think in that case there is no difference to bash):
for FIELD in `echo "select column_with_varchar_type from table" | mysql MYDATABASE`
do
echo "FIELD: $FIELD"
done
This works fine for normal strings, but it fails for an entry where star ("*") is in column_with_varchar_type, then dash expands this to use all files in the current working directory which is of course completely wrong.
Is there a way to prevent the shell expansion or replace the star with something else in the mysql-query?
Clarification: I do NOT want to select all columns "select *", but I want to select all entries of one column and one of these entries is a string that is a star. The input to the query does not contain any stars and is fine, the problem lies in the output of the query.
For example, if the table contains the strings "aaa", "bbb" and "*", a typical output may be:
FIELD: aaa
FIELD: bbb
FIELD: Makefile
FIELD: src
FIELD: some_other_file_that_happens_to_be_in_the_working_directory.txt
So I get the strings "aaa" and "bbb" (correct), but "*" is missing and is replaced with whatever garbage is in the working directory.
Updated
As discussed in comments, this can be an approach:
while read -r field
do
echo "FIELD: $field"
done < <(echo "select column_with_varchar_type from table" | mysql MYDATABASE)
Because the problem was with the data coming from the query, not from the query itself. Hence, it is necessary to handle the strings with * that are coming from such query and while -r solves it.
The problem is that * gets expanded by the shell when it is within double quotes.
You can use single quotes instead:
for FIELD in $(echo 'select * from table' | mysql MYDATABASE)
do
do_something
done
Note you could also use -e option:
mysql MYDATABASE -e 'select * from table'
try this:
for FIELD in `echo 'select \* from table' | mysql MYDATABASE`
do
do_something
done
The solution is to add quotes in the MySQL-query:
for FIELD in `mysql MYDATABASE -e 'select concat(concat("\"", column_with_varchar_type), "\"") from table'`
do
echo "FIELD: $FIELD"
done
In PhpMyAdmin I use this query:
SELECT * FROM myrecords where TITLE LIKE "%\\\"%"
To filter out badly saved records that have " sign escaped with \ sign. It should be just ". So I need to find only these records with \" and replace it with " only. But when I use the query above to filter the \" I get records with \" as well like the records with ".
How to make this query get only records with \" and not " alone?
#paul correct me, and it's this way:
SELECT t1.title FROM myrecords as t1 where replace(title,'\\\"','#') LIKE "%#%";
This is the right query to search for \" :
SELECT * FROM myrecords where TITLE LIKE '%\\\\\\\"%';
From MySQL documentation:
"To search for “\”, specify it as “\\\\”; this is because the
backslashes are stripped once by the parser and again when the pattern
match is made, leaving a single backslash to be matched against. "