I tried to select a data which is in column "fileName" and its fileName is '2016-11-22-12-55-09_hyun.png'
I tired the
select * from images where 'fileName' like '2016-11-22-12-55-09_hyun.png'
However it can not select anything, nor has any kind of error info.
How can I select this file with its filename? Thank you so much.
Single quotes denote a string literal. So in this query you aren't evaluating the column filename, but checking whether the string 'filename' is like the string '2016-11-22-12-55-09_hyun.png', which it of course is not. Just drop the quotes from filename and you should be OK. Also note that since you aren't using any wildcards, using the like operator is pretty pointless, and you could (should) just a plain old equality check:
select * from images where fileName = '2016-11-22-12-55-09_hyun.png'
-- No quotes -------------^--------^
Related
For people who tried or needed a solution to escape every special character (even $) in a WHERE CLAUSE in POSTGRESQL, here is how it should be use
the documentation can be somehow hard to understand, and there is no proper example of it so here is mine
e.g : if you want to make a request looking as
SELECT
*
FROM
<TableName>
WHERE
<ColumnName> = 'string with ' character';
it will throw an error cause "character'" is outside the string
So here is how it should be written:
SELECT
*
FROM
<TableName>
WHERE
<ColumnName> = $$string with ' character$$;
The WHERE CONDITION will take the string literally; the interface may look broken but the following instruction will still be interpreted as expected.
SELECT
*
FROM
<TableName>
WHERE
<ColumnName> = $$string with ' character$$ AND <OtherColumnName> IS NOT NULL;
This could even be another escaped string with $$.
For details about dollar quoting, look at the documentation.
I may have an odd request. I'm not finding any help via Google.
I am using the DbVisualizer Pro 10.0.15 gui tool connected to a PostgreSQL db.
I need to create a csv file from a database table. I select the records I need in a query then export the results to a .csv file. I can do that easy.
select note from notes;
highlight all results records >> right-click >> select export >> choose csv
Some of the records have both single and/or double-quotes in the content.
The person receiving this file needs to upload the csv file into another system. They are stating that these single and double-quotes in the content will not work in their upload. I've been asked to escape these quotes. They want to keep them in the content, but have them appear in the field with the backslash escape character, i.e: it is John's ball would show in the csv file as: it is John\'s ball. The same for dbl-quotes.
I could probably do this with a search-and-replace function in a text editor after creating the csv file, but I'd like to think this can be done via sql.
I've tried playing with the regexp_replace() function.
select regexp_replace(note, '"', '\"') as notes from notes works on the dbl-quotes, but I'm not having any luck on the single quotes.
Help? Is there a way to do this?
You can escape double quotes by doing:
postgres=# SELECT REGEXP_REPLACE('this "is" a string', '"', '\"', 'g');
regexp_replace
----------------------
this \"is\" a string
(1 row)
For single quotes, the approach is similar, but you have to escape them using another single quote. So instead of having something like /', it should be ''. The query is:
postgres=# SELECT REGEXP_REPLACE('this ''is'' a string', '''', '\''', 'g');
regexp_replace
----------------------
this \'is\' a string
(1 row)
Note the 'g' flag in the end, this forces it to replace all occurrences and not just the first one found.
You can also replace both single and double quotes in a single statement, although they are replaced with the same string (\" in this case).
postgres=# SELECT REGEXP_REPLACE('this "is" a ''normal'' string', '["'']', '\"', 'g');
regexp_replace
---------------------------------
this \"is\" a \"normal\" string
(1 row)
I'm trying to export data to csv from clickhouse cli.
I have a field which is string and when exported to CSV this field has quotes around it.
I want to export without the quotes but couldn't find any setting that can be set.
I went through https://clickhouse.yandex/docs/en/interfaces/formats but the Values section mentions
Strings, dates, and dates with times are output in quotes
While for JSON they have a flag that is to be set for removing quotes around Int64 and UInt64
For compatibility with JavaScript, Int64 and UInt64 integers are enclosed in double quotes by default. To remove the quotes, you can set the configuration parameter output_format_json_quote_64bit_integers to 0.
I was wondering if there is such kind of flag for strings in CSV as well.
I'm exporting using the below command
clickhouse client --multiquery --host="localhost" --port="9000" --query="SELECT field1, field2 from tableName format CSV" > /data/content.csv
I want to try removing the quotes from the shell as the last thing if nothing works.
Any help on the way I can remove the quotes while the CSV is generated would be appreciated.
Nope, there isn't. However you can easily achieve this by arrayStringConcat.
SELECT arrayStringConcat([toString(field1), toString(field2)], ',') from tableName format TSV;
Edit
In order to make Nullable output as empty string, you might need if function.
if(isNull(field1), '', assumeNotNull(field1))
This works for any types, while assumeNotNull alone only works for String
I have a table with camelCased column names (which I now deeply regret). If I use double quotation marks around the column names as part of the SELECT clause, they work fine, e.g. SELECT "myCamelCasedColumn" FROM the_table;. If, however, I try doing the same in the WHERE clause, then I get an error.
For example, SELECT * FROM the_table WHERE "myCamelCasedColumn" = "hello"; gives me the error column "hello" does not exist.
How can I get around this? If I don't surround the column in double quotation marks then it will just complain that column mycamelcasedcolumn does not exist.
In SQL string literals are enclosed in single quotes, not double quotes.
SELECT *
FROM the_table
WHERE "myCamelCasedColumn" = 'hello';
See the manual for details:
http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
The manual also explains why "myCamelCasedColumn" is something different in SQL than myCamelCasedColumn
In general you should stay away from quoted identifiers. They are much more trouble than they are worth it. If you never use double quotes everything is a lot easier.
The problem is you use double quote for strin literal "hello". Should be 'hello'. Double quotes is reserved for identifiers.
I have a query:
SELECT phone,
to_char(appt_date,'MM/DD/YYYY'),
time_text,
staff_email || subject_line as title,
staff_wav,
agency_wav
FROM phone_dialer
that is sent to a csv file
That results in
9105554444,07/01/2011,08:30am,me#myemail.orgGADK082493,staffid0827,Coastal Counseling
or
9105554444,07/01/2011,08:30am,me#myemail.orgGADK082493,staffid0827,Smith, Bob
The "agency_wav" column could have a name of company. I have tried several ways to remove the comma between Smith, Bob and am failing miserably.
Can anyone steer me to a resolution?
Answer to title, since the body of the question is unclear.
Fastest way to remove commas from a string:
SELECT translate('Smith, Bob, foo,,,bar', ',', '');
Related answer addressing translate() / replace():
Looking for phone number containing a minus, like "123-456789"
If your surround your query with the syntax COPY () TO STDOUT WITH CSV; then it will construct the CSV output and automatically quote the field values that contain commas.
If you want to manually do it in the query, try replace(agency_wav,',','').
The preferred way to create CSV is to use COPY command.
If by some reason you don't want or can't use it, you just need make value returned in the column CSV friendly that is enclose value in double quotes and escape existing double quotes by duplicating them in the string. This will preserve correct value (that is all commas) but will not break CSV format.
SELECT phone,
to_char(appt_date,'MM/DD/YYYY'),
time_text,
staff_email || subject_line as title,
staff_wav,
'"' || replace(agency_wav, '"', '""') || '"'
FROM phone_dialer
This will produce the following line
9105554444,07/01/2011,08:30am,me#myemail.orgGADK082493,staffid0827,"Smith, Bob"
Note quoted value which has comma.