Why does "UPDATE Users SET Password=? WHERE Username=?" give a syntax error? [duplicate] - visual-studio

One of my columns is called from. I can't change the name because I didn't make it.
Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused?

Wrap the column name in brackets like so, from becomes [from].
select [from] from table;
It is also possible to use the following (useful when querying multiple tables):
select table.[from] from table;

If it had been in PostgreSQL, use double quotes around the name, like:
select "from" from "table";
Note: Internally PostgreSQL automatically converts all unquoted commands and parameters to lower case. That have the effect that commands and identifiers aren't case sensitive. sEleCt * from tAblE; is interpreted as select * from table;. However, parameters inside double quotes are used as is, and therefore ARE case sensitive: select * from "table"; and select * from "Table"; gets the result from two different tables.

These are the two ways to do it:
Use back quote as here:
SELECT `from` FROM TableName
You can mention with table name as:
SELECT TableName.from FROM TableName

While you are doing it - alias it as something else (or better yet, use a view or an SP and deprecate the old direct access method).
SELECT [from] AS TransferFrom -- Or something else more suitable
FROM TableName

Your question seems to be well answered here, but I just want to add one more comment to this subject.
Those designing the database should be well aware of the reserved keywords and avoid using them. If you discover someone using it, inform them about it (in a polite way). The keyword here is reserved word.
More information:
"Reserved keywords should not be used
as object names. Databases upgraded
from earlier versions of SQL Server
may contain identifiers that include
words not reserved in the earlier
version, but that are reserved words
for the current version of SQL Server.
You can refer to the object by using
delimited identifiers until the name
can be changed."
http://msdn.microsoft.com/en-us/library/ms176027.aspx
and
"If your database does contain names
that match reserved keywords, you must
use delimited identifiers when you
refer to those objects. For more
information, see Identifiers (DMX)."
http://msdn.microsoft.com/en-us/library/ms132178.aspx

In Apache Drill, use backquotes:
select `from` from table;

If you ARE using SQL Server, you can just simply wrap the square brackets around the column or table name.
select [select]
from [table]

I have also faced this issue.
And the solution for this is to put [Column_Name] like this in the query.
string query= "Select [Name],[Email] from Person";
So it will work perfectly well.

Hi I work on Teradata systems that is completely ANSI compliant. Use double quotes " " to name such columns.
E.g. type is a SQL reserved keyword, and when used within quotes, type is treated as a user specified name.
See below code example:
CREATE TABLE alpha1
AS
(
SEL
product1
type_of_product AS "type"
FROM beta1
) WITH DATA
PRIMARY INDEX (product1)
--type is a SQL reserved keyword
TYPE
--see? now to retrieve the column you would use:
SEL "type" FROM alpha1

I ran in the same issue when trying to update a column which name was a keyword. The solution above didn't help me. I solved it out by simply specifying the name of the table like this:
UPDATE `survey`
SET survey.values='yes,no'
WHERE (question='Did you agree?')

The following will work perfectly:
SELECT DISTINCT table.from AS a FROM table

Some solid answers—but the most-upvoted one is parochial, only dealing with SQL Server. In summary:
If you have source control, the best solution is to stick to the rules, and avoid using reserved words. This list has been around for ages, and covers most of the peculiarities. One tip is that reserved words are rarely plural—so you're usually safe using plural names. Exceptions are DIAGNOSTICS, SCHEMAS, OCTETS, OFFSETS, OPTIONS, VALUES, PARAMETERS, PRIVILEGES and also verb-like words that also appear plural: OVERLAPS, READS, RETURNS, TRANSFORMS.
Many of us don't have the luxury of changing the field names. There, you'll need to know the details of the RDBM you're accessing:
For SQL Server use [square_braces] around the name. This works in an ODBC connection too.
For MySQL use `back_ticks`.
Postgres, Oracle and several other RDBMs will apparently allow "double_quotes" to be used.
Dotting the offending word onto the table name may also work.

You can put your column name in bracket like:
Select [from] from < ur_tablename>
Or
Put in a temprary table then use as you like.
Example:
Declare #temp_table table(temp_from varchar(max))
Insert into #temp_table
Select * from your_tablename
Here I just assume that your_tablename contains only one column (i.e. from).

In MySQL, alternatively to using back quotes (`), you can use the UI to alter column names. Right click the table > Alter table > Edit the column name that contains sql keyword > Commit.
select [from] from <table>
As a note, the above does not work in MySQL

Judging from the answers here and my own experience. The only acceptable answer, if you're planning on being portable is don't use SQL keywords for table, column, or other names.
All these answers work in the various databases but apparently a lot don't support the ANSI solution.

Simple solution
Lets say the column name is from ; So the column name in query can be referred by table alias
Select * from user u where u.from="US"

In Oracle SQL Developer, pl/sql you can do this with double quotes but if you use double quotes you must type the column names in upper case. For example, SELECT "FROM" FROM MY_TABLE

Related

how to specifically define table name in Oracle SQL

i have a DB which has a table named LIKE.
uppon trying to execute any query on the table, it gives me an error and i know it's because of the name which is trying to use the query keyword LIKE.
Now, i have "bypassed" this issue in MySQL by just selecting the table as
SELECT tk_oseba_id, COUNT(tk_tip_like_id) AS St_Like_haha
FROM student999.`like`;
Now this same line wont work at `l...is there any special way to to this in oracle or how can i manipulate with the table by not using the LIKE keyword.
Oracles's counter part to mysql's back tick is quote for defining tablenames/columns.
To use a key word as a table name though I recommend against it...
wrap the table name in quotes. From student9999."like"
AND... it forces case sensitivity when you use the quotes!

Oracle SQL Developer lowercase identifiers for migrated DBs?

I'm currently porting a Code Igniter based application from MySQL to Oracle (11g) for a specific client. Both the MySQL and Oracle back-ends have to work in conjunction (i.e. we cannot drop the one or the other).
The MySQL DB uses around 100 tables of which ALL identifiers are in lowercase. When I migrate this DB to Oracle, using Oracle's SQL Developer tool, I end up with a 'properly' converted DB, but... with all uppercase identifiers.
Now, for normal usage this isn't really a problem, but the issue arises when using the CI Active Record class. It generates queries to the effect of:
SELECT "somecolumn" FROM "sometable" WHERE "someothercolumn" = somevalue
The issue is that when the " quotes are used for these identifiers, Oracle forces these identifiers to be interpreted in a case sensitive way, which in this case is wreaking havoc.
Patching the core code of CI and/or the application to either make all queries use case insensitive identifiers (i.e. by dropping the usage of the " quotes around the identifiers) or to convert all identifiers to uppercase ones on the fly, is IMO not desired, as a potential future framework upgrade is then compromised. Renaming ALL MySQL identifiers to become in uppercase is also a very unattractive scenario and has an even bigger impact on the application itself -- not an option for sure.
Instead, what I would like to achieve, is to have the migration process (i.e. using SQL Developer) simply respecting the case of the source DB and to perform the conversion exactly as it does up to now, with the exception that the identifiers do not get changed to their uppercase version.
I have searched a fair deal online to find a way to achieve this, and so far it has been to no avail.
Does anyone know if this can be done, and if so: how?
Is the conversion to all uppercase identifiers by any chance a global DB setting, perhaps?
I would have assumed this to be a trivial thing, but I haven't been able to figure it out so far and what little related references that I did come across do not sound very promising...
If you can acquire a schema script created by the database migration all you need to do is change the identifiers ( tablenames, view names, column names etc ) to be surrounded with double quotation marks. (I'm not sure if SQL Developer migrations actually has the option to preserve the case).
Without the quote marks Oracle will assume all identifiers are case-insensitive. However this is stored internally as upper case strings in the data dictionary. By using quote marks will force Oracle to use the exact case for the schema objects.
eg.
create table Customers
(
Name varchar2(100),
CreationDate date not null
);
will create CUSTOMERS internally in the data-dictionar and you can write queries like:
select name, creationdate from customers;
alternatively:
create table "Customers"
(
"Name" varchar2(100),
"CreationDate" date not null
);
will create "Customers" internally. You can only write queries using quotes and exact case:
select "Name", "CreationDate" from "Customers";
I have hit this before and simply edited oci8_driver.php (../system/database/oci) as follows:
// The character used for excaping
var $_escape_char = '"';
to
// The character used for excaping
var $_escape_char = '';
Stewart

Is it possible to determine which database objects were created with quoted identifiers in Oracle?

I have a schema in which a small number of the thousands of stored procedures have been created with quoted identifiers. I need to fix them. The only way I currently have of identifying them is by opening them up in SQLDeveloper, one at a time, and checking to see if the CREATE OR REPLACE... bit at the top has quotes around the procedure name. Does anyone have any cunning method of identifying these troublesome objects more easily? Have I overlooked some Oracle system view with a this_uses_quoted_identifiers flag, perhaps? Please enlighten me!
There are at least 2 ways:
select * from all_source where type = 'PROCEDURE' and line = 1 and text like '%"%'
and
select * from all_procedures where procedure_name != upper(procedure_name)
However, none of them is 100% correct and complete. The first one looks for any double quote in the first line. The second one would only find procedures with lower caps in their name which would mean that double quotes have been used.
As far as I know, if you quote an identifier, but all the letters are in capital form, it is just equivalent to non quoted identifier.
So you can select from ALL_OBJECTS to see which object names have names with non capital letters.

PostgreSQL - query syntax without quotes

I have a little silly question. I have installed a PostgreSQL DB Server, but when I run query, there is a problem with column identifier without quotes. I don't know why the quotes around identifiers are needed. My query:
SELECT vc."CAR_ID"
FROM "VEL_CAR" vc, "VEL_DRIVER" vd, "VEL_DRIVER_CAR" vdc
WHERE vc."CAR_ID" = vdc."CAR_ID" and
vdc."DRIVER_ID" = vd."DRIVER_ID";
My practice from Oracle DB is not to use ". So in Oracle:
SELECT vc.CAR_ID
FROM VEL_CAR vc, VEL_DRIVER vd, VEL_DRIVER_CAR vdc
WHERE vc.CAR_ID = vdc.CAR_ID and
vdc.DRIVER_ID = vd.DRIVER_ID;
When I run this query without quotes in PostgreSQL it throws error about syntax:
ERROR: column vc.car_id does not exist
LINE 1: SELECT vc.CAR_ID
Do you know why?
--SOLVED--
Thank you, now I solved the problem! It was about table creation. I created table objects using pgAdminIII and i wrote table name and column names uppercased. pgAdminIII created query with quotas - because of the names was uppercased. So query had to be written with quotas.
When you create your tables using double quotes, column and table names become case sensitive. So "car_id" is a different name than "CAR_ID"
You need to create your tables without using double quotes, then the names are not case sensitive: car_id is the same as CAR_ID (note the missing quotes!)
See the manual for details:
http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
Edit:
Oracle behaves just the same way. The only difference is that Oracle stores names in upper case and Postgres stores them in lower case. But the behaviour when using quotes is identical.
From Postgres documentation :
Quoting an identifier also makes it case-sensitive, whereas unquoted names are always folded to lower case. For example, the identifiers FOO, foo, and "foo" are considered the same by PostgreSQL, but "Foo" and "FOO" are different from these three and each other. (The folding of unquoted names to lower case in PostgreSQL is incompatible with the SQL standard, which says that unquoted names should be folded to upper case. Thus, foo should be equivalent to "FOO" not "foo" according to the standard. If you want to write portable applications you are advised to always quote a particular name or never quote it.)
Seems to me that the table vc does not have a column named car_id. Are you sure it is there? Do \d vel_car to see the structure of the table.
The quotes are optional and you can usually skip them.

ORA-12704: Unable to convert character data

I am trying to perform SET operations in Oracle across remote databases.
I am using the MINUS operator.
My query looks something like this.
SELECT NAME FROM localdb MINUS SELECT NAME from remotedb#dblink
This is throwing up a ORA-12704 error. I understand this warrants some kind of conversion or a NLS Setting.
What should I try next?
The two name columns are stored in different characters sets. This could be because of their type definitions, or it could be because the two databases are using different character sets.
You might be able to get around this by explicitly converting the field from the remote database to the character set of the local one. Try this:
SELECT NAME FROM localdb MINUS SELECT TO_CHAR(NAME) from remotedb#dblink
It seams the types of NAME column in those 2 tables are different.
Make sure the NAME column in the remotedb table is exactly the same type as the NAME in localdb table. It is mandatory when you use a MINUS operator.

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