I am working with a malformed database which seems to have double quotes as part of the column names.
Example:
|"Market" |
|---------|
|Japan |
|UK |
|USA |
And I want to select like below
SELECT "\"Market\"" FROM mytable; /* Does not work */
How does one select such a thing?
The documentation says
[A] delimited identifier or quoted identifier […] is formed by enclosing an arbitrary sequence of characters in double-quotes ("). […]
Quoted identifiers can contain any character, except the character with code zero. (To include a double quote, write two double quotes.)
So you'll want to use
SELECT """Market""" AS "Market" FROM mytable;
An alternative would be
A variant of quoted identifiers allows including escaped Unicode characters identified by their code points. This variant starts with U& (upper or lower case U followed by ampersand) immediately before the opening double quote, without any spaces in between, for example U&"foo". […] Inside the quotes, Unicode characters can be specified in escaped form by writing a backslash followed by the four-digit hexadecimal code point number or alternatively a backslash followed by a plus sign followed by a six-digit hexadecimal code point number.
which in your case would mean
SELECT U&"\0022Market\0022" AS "Market" FROM mytable;
SELECT U&"\+000022Market\+000022" AS "Market" FROM mytable;
Disclaimer: your database may not actually have double quotes as part of the name itself. As mentioned in the comments, this might just be the way in which the tool you are using does display a column named Market (not market) since
Quoting an identifier also makes it case-sensitive
So all you might need could be
SELECT "Market" FROM mytable;
Related
I'm trying to match a certain text that includes a single quote (i.e. 'company's report...')
normally I would have used the E' literal + ' or double single quotes.
but when it gets to using the LIKE '%' operator, things got complicated.
what is the best approach to match a text with a single quote?
You can escape single quote with another single quote. Example:
WHERE column LIKE 'RSNboim''s'
From https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS
To include a single-quote character within a string constant, write two adjacent single quotes, e.g., 'Dianne''s horse'. Note that this is not the same as a double-quote character (").
You can use Dollar-quoted String Constants at Lexical Structure
Your condition should be something like below;
select * from atable
where afield like $$Dianne's %$$
Would like to be able to add characters like '-' in the schema name when running COPY command in postgresSQL. Any way to get around this ? Thanks!
`psql -d postgres -c "\COPY (SELECT * FROM test-schema.tableName) TO data.csv DELIMITER ',' CSV"
ERROR: syntax error at or near "-"`enter code here`
LINE 1: COPY ( SELECT * FROM test-schema.tableName ) TO STDOUT DELIMITER ',...`
Yes though I tend to discourage it.
Identifiers:
SQL identifiers and key words must begin with a letter (a-z, but also letters with diacritical marks and non-Latin letters) or an underscore (_). Subsequent characters in an identifier or key word can be letters, underscores, digits (0-9), or dollar signs ($). Note that dollar signs are not allowed in identifiers according to the letter of the SQL standard, so their use might render applications less portable. The SQL standard will not define a key word that contains digits or starts or ends with an underscore, so identifiers of this form are safe against possible conflict with future extensions of the standard.
There is a second kind of identifier: the delimited identifier or quoted identifier. It is formed by enclosing an arbitrary sequence of characters in double-quotes (").
So:
create schema "test-schema";
CREATE SCHEMA
\dn "test-schema"
List of schemas
Name | Owner
-------------+----------
test-schema | postgres
create table "test-schema"."test-table"(id int);
select * from test-schema."test-table";
ERROR: syntax error at or near "-"
LINE 1: select * from test-schema."test-table";
select * from "test-schema"."test-table";
id
----
(0 rows)
As you see, if you double quote an identifier to get around the identifier naming rules then you are bound to always quoting it.
I have the following string in my DB, in a column we will name 'info', in a table we can call 'conversation':
Hello, I''''''''''''''''m Brian and I''''m looking for the kitchen
I would like to know if it's possible to replace the '''''' to a single occurrence of itself in PostgreSQL.
So:
Hello, I'm Brian and I'm looking for the kitchen
You can use regexp_replace for that:
select regexp_replace(info, '''+', '''', 'g')
from conversation;
The regular expression looks a bit weird due to the escaping of the single quotes, but it essentially is: '+ which means "at least one single quoted followed by any number of single quotes" and the replacement values (third parameter) is just one single quote.
Online example: https://rextester.com/HGWDZ41975
I'm trying to insert some data into my table using the copy command :
copy otype_cstore from '/tmp/otype_fdw.csv' delimiter ';' quote '"' csv;
And I have this answer :
ERROR: unterminated CSV quoted field
There is the line in my CSV file where I have the problem :
533696;PoG;-251658240;from id GSW C";
This is the only line a double quote and I can't remove it, so do you have some advice for me ?
Thank you in advance
If you have lines like this in your csv:
533696;PoG;-251658240;from id GSW C";
this actually means/shows the fields are not quoted, which is still perfectly valid csv as long as there are no separators inside the fields.
In this case the parser should be told the fields are not quoted.
So, instead of using quote '"' (which is actually telling the parser the fields are quoted and why you get the error), you should use something like quote 'none', or leave the quote parameter out (I don't know Postgres, so I can't give you the exact option to do this).
Ok, I did a quick lookup of the parameters. It looks like there is not really an option to turn quoting off. The only option left would be to provide a quote character that is never used in the data.
quote E'\b' (backspace) seems to work ok.
Bit late to reply, but I was facing same issue and found that for double quote we need to add one more double quote to escape with along with prefix and suffix double quote to that special characater. for your case it would be
input data is : from id GSW C"
change data to : from id GSW C""""
note there are 4 consecutive double quotes.
first and last double quote is prefix and postfix as per documentation.
middle 2 double quotes is data with one escape double quote.
Hope this helps for readers with similar issue going forward.
So for every double quote in data it needs to be escaped with one escape character (default double quote). This is as per documentation.
I have a database entry that has entries that look like this:
id | name | code_set_id
I have this particular entry that I need to find:
674272310 | raphodo/qrc_resources.py | 782732
In my rails app (2.3.8), I have a statement that evaluates to this:
SELECT * from fyles WHERE code_set_id = 782732 AND name LIKE 'raphodo/qrc\\_resources.py%';
From reading up on escaping, the above query is correct. This is supposed to correctly double escape the underscore. However this query does not find the record in the database. These queries will:
SELECT * from fyles WHERE code_set_id = 782732 AND name LIKE 'raphodo/qrc\_resources.py%';
SELECT * from fyles WHERE code_set_id = 782732 AND name LIKE 'raphodo/qrc_resources.py%';
Am I missing something here? Why is the first SQL statement not finding the correct entry?
A single backslash in the RHS of a LIKE escapes the following character:
9.7.1. LIKE
[...]
To match a literal underscore or percent sign without matching other characters, the respective character in pattern must be preceded by the escape character. The default escape character is the backslash but a different one can be selected by using the ESCAPE clause. To match the escape character itself, write two escape characters.
So this is a literal underscore in a LIKE pattern:
\_
and this is a single backslash followed by an "any character" pattern:
\\_
You want LIKE to see this:
raphodo/qrc\_resources.py%
PostgreSQL used to interpret C-stye backslash escapes in strings by default but no longer, now you have to use E'...' to use backslash escapes in string literals (unless you've changed the configuration options). The String Constants with C-style Escapes section of the manual covers this but the simple version is that these two:
name LIKE E'raphodo/qrc\\_resources.py%'
name LIKE 'raphodo/qrc\_resources.py%'
do the same thing as of PostgreSQL 9.1.
Presumably your Rails 2.3.8 app (or whatever is preparing your LIKE patterns) is assuming an older version of PostgreSQL than the one you're actually using. You'll need to adjust things to not double your backslashes (or prefix the pattern string literals with Es).