Related
I do voluntary work at an animal shelter. We have an application which uses a SQL Server 2019 database. I have created a view that includes a varbinary(max) column. The value in this column is a picture, stored in hexadecimal-format. I would like to convert this Hex-value to a base64-binary file and add these to the view as an extra column.
I found the perfect solution for my situation in SQL Server : hex to base64. The example provided converts 1 single hex-value into 1 base64-value. I now need to add this solution to my view, but I'm not having any success.
The offered solution:
DECLARE #TestBinHex varchar(max), #TestBinary varbinary(max), #Statement nvarchar(max);
SELECT #TestBinHex = '0x012345';
SELECT #Statement = N'SELECT #binaryResult = ' + #TestBinHex;
EXECUTE sp_executesql #Statement, N'#binaryResult varbinary(max) OUTPUT', #binaryResult=#TestBinary OUTPUT;
SELECT
CAST(N'' AS XML).value(
'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
, 'VARCHAR(MAX)'
) Base64Encoding
FROM
(SELECT #TestBinary AS bin) AS bin_sql_server_temp;
A simplified version of my view:
SELECT
a.cat_id, a.catname, s.cat_id,
s.stay_id, s.shelter_handler, s.shelter_kennel, s.picture
FROM
dbo.animal AS a
OUTER APPLY
(SELECT TOP 1 *
FROM dbo.shelterdata
WHERE a.cat_id = s.cat_id
ORDER BY s.stay_id DESC) AS S
WHERE
(a.cat_id IS NOT NULL) AND (s.leave_date IS NULL)
The view shows an overview of all cats currently present in the shelter (leave_date is NULL). The reason for the TOP 1 is that sometimes shelter animals get returned, and the application then assigns a new stay_id. To prevent duplicate values from the join, I only return the value of the most recent stay_id.
What I am trying to achieve: the second table (dbo.shelterdata) includes the picture, stored in hex value. I'd like to add a column Base64Encoding to the view which includes the converted value.
My attempts
I was successful in replacing the static value '0x012345' by a SELECT statement. But the way the solution is formatted, it only allows for one input value. So I had to restrict it with a WHERE clause. It is obvious to me that I need to make a subquery which inputs the hex value based on the unique cat_id. However, it has been many years since I worked with variable, so I'm struggling with the formatting of the statement.
My request
Does anyone have a suggestion how to build the conversion into the view?
Any assistance would be greatly appreciated.
After searching for a few more hours, I stumbled onto the solution. Maybe it will help someone else in the future. The solution is remarkably simple, as is often the case.
My view, mentioned above, is called dbo.shelter_view
select sv.picture,sv.cat_id,
cast('' as xml).value(
'xs:base64Binary(sql:column("sv.picture"))', 'varchar(max)'
) as Base64Encoding
from dbo.shelter_view as SV
I have two broad questions:
Q1. Are executing the lines of code in Oracle SQL Developer and executing the same code in sqlplus command prompt same things?
(reason I ask this that I heard that not all the sqlplus commands are executable in SQL Developer. If answer to above question is yes then please then few useful links will help).
Q2. I am spooling the results of a sql query to a .csv file, but the thing is that columns names are truncated according the maximum length of the values in that column.
My code is:
set colsep ","
spool C:\Oracle\sample.csv
select * from acct_clas_rule;
spool off;
Output of above code is (middle column is having null values)
ABCD_,ABCD_,ABC
-----,-----,---
AB , ,WSD
ABCD , ,WSD
ABCD , ,WSD
SG , ,WSD
KD , ,WSD
WD , ,LKJ
KLHGF, ,LKO
WSDFG, ,LOK
WSDF , ,LKO
WS , ,GH
In above output, columns names have been truncated. I want full names of the columns to be displayed. Can anyone help?
I have seen the question in this link, but I didn't understand how to apply the answers provided there as there was no particular example cited. I am new to these things so I couldn't understand.
Original names of my columns (from left to right in above table) are :
ABCD_DFGT_SDF, ABCD_EDF_GH, ABCD_DFRE
PS -
1. I am using Oracle SQL developer to run sqlplus commands. I think because of which few of my commands are not working (like set underline, set linesize etc.).Please let me know if this is the case. I actually want remove those underlines beneath the columns names.
2. Also let me know that whether you answer is applicable to Oracle SQL Developer or sqlplus.
Thank You
There are a couple of things you can do, in addition to #JChomel's approach - that will work in either SQL Develoepr or SQL*Plus, while these suggestions are specific to SQL Developer.
Let's start with a dummy query based on a CTE to get something like your situation:
set colsep ","
with acct_clas_rule (abdc_1, abcd_2, abcd_3) as (
select cast('AB' as varchar2(5)), cast(null as varchar2(5)), cast('WSD' as varchar2(4)) from dual
union all select 'ABCD', null, 'WSD' from dual
-- ...
union all select 'WS', null, 'GH' from dual
)
select * from acct_clas_rule;
When run as a script in SQL Developer (from the document+arrow icon, or F5) the output is:
ABDC_,ABCD_,ABCD
-----,-----,----
AB , ,WSD
ABCD , ,WSD
WS , ,GH
If you change the query to include the SQL Developer-specific formatting hint /*csv*/ then you get the output you want:
select /*csv*/ * from acct_clas_rule;
"ABDC_1","ABCD_2","ABCD_3"
"AB","","WSD"
"ABCD","","WSD"
"WS","","GH"
except that the strings are all enclosed in double-quotes, which might not be what you really want. (It depends what you're doing with the spooled file and whether any of your string values contain commas, which would confuse Excel for instance).
With more recent versions of SQL Developer you can get exactly the same result without modifying the query using the sqlformat option:
set sqlformat csv
select * from acct_clas_rule;
but again you get the double-quotes. You could change the double-quotes to different enclosure characters, but that probably doesn't help.
A different approach is to use the built-in export tools instead of spool. If you run the query as a statement (green 'play button' icon, or control-enter) then rather than appearing in the Script Output panel, a new Query Result panel will open next to that, showing the results as a grid.
If you right-click on the results you'll get a contextual menu, and choosing Export... from that will give you a wizard to export the results in a format of your choice, including CSV:
You can leave the left and right enclosures as double-quotes to get the same results as the options above, except that null values use the word 'null' instead of an empty string:
"ABDC_1","ABCD_2","ABCD_3"
"AB",null,"WSD"
"ABCD",null,"WSD"
"WS",null,"GH
or you can change them, or remove them by choosing 'none', which gives you:
ABDC_1,ABCD_2,ABCD_3
AB,null,WSD
ABCD,null,WSD
WS,null,G
#thatjeffsmith has commented on how to change the null-replacement text for the /*csv*/ approach. For export it looks like having the word 'null' might have been a bug in 17.2.0; in 17.3.1 that does not appear, and instead you see:
ABDC_1,ABCD_2,ABCD_3
AB,,WSD
ABCD,,WSD
WS,,GH
or enclosed empty strings ("") if you leave the enclosures set.
Q1: TI'm not an expert of SQL Developer. There might be a mode like "command line" or something where you could get similar result, but unsure.
Q2: You have to set the right option to sqlplus: here is a trick I know of (it will also remove the --- --- --- that will cause other issue):
SET HEADING OFF`, to avoid column name to be printed
Union all the column names at the beginning of your script:
set colsep ","
spool C:\Oracle\sample.csv
select 'ABCD_DFGT_SDF', 'ABCD_EDF_GH', 'ABCD_DFRE' from dual
UNION ALL
select * from acct_clas_rule;
spool off;
use the sql plus set command -----> set underline off
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
I need to work with a SQL result set in order to do some processing for each column (medians, standard deviations, several control statements included)
The SQL is dynamic so I don't know the number of columns, rows.
First I tried to use temporary tables, views, etc to store the results, however I did not manage to overcome the 30 character limit of Oracle columns when using the below sql:
create table (or view or global temporary table) as select * from (
SELECT
DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE,
SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ +DMTTBF_MAT_MATURATO_BILL_POS. MAT_N_NUM_EVENTI) <-- exceeds the 30 character limit
FROM DMTTBF_MAT_MATURATO_BILL_POS
WHERE DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE >= '201301'
GROUP BY DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE
)
Second choice was to use some PL/SQL types to store the entire table information, so I could call it like in other programming languages (e.g. a matrix result[i][j]) but I could not find anything similar.
Third variant, using files for reading and writing: i did not try it yet; i'm still expecting a more elegant pl/sql solution
It's possible that I have the wrong approach here so any advice is more than welcome.
UPDATE: Modifying the input SQL is not an option. The program has to accept any select statement.
Note that you can alias both tables and fields. Using a table alias keeps references to it from producing walls of text in the query. Using one for a field gives it a new name in the output.
SELECT A.LONG_FIELD_NAME_HERE AS SHORTNAME
FROM REALLY_LONG_TABLE_NAME_HERE A
The auto naming adds _1 and _2 etc to differentiate the same column name coming from different table references. This often puts a field already borderline over the limit. Giving the fields names yourself bypasses this.
You can put the alias also in dynamic SQL:
sqlstr := 'create table (or view or global temporary table) as select * from (
SELECT
DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE,
SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ + DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI) AS '||SUBSTR('SUM(DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI_CHZ +DMTTBF_MAT_MATURATO_BILL_POS.MAT_N_NUM_EVENTI)', 1, 30)
||' FROM DMTTBF_MAT_MATURATO_BILL_POS
WHERE DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE >= ''201301''
GROUP BY DMTTBF_MAT_MATURATO_BILL_POS.MAT_V_COD_ANNOMESE
)'
This question may be Toad specific. I have no idea how Oracle stores views, so I'll explain what happens when I use Toad. If I get an answer that is Oracle specific, so much the better.
I have created a rather complex view. To make it clearer, I have formatted the code nicely, and entered some comments where needed. When I need to make changes to the view, I use Toad's "describe objects" window, where I can find a script to recreate the view. The only problem is that all my formatting is gone. Comments before the select keyword (but after "create view xxx as") will also disappear.
If I enter this script to create a view:
create or replace view TestViewFormatting as
-- Here I have a long comment explaining the role of the
-- view and certain things to be aware of if changing it.
-- Unfortunately this comment will disappear...
select
name, --This comment will be kept
accountnumber --This also
from
debtable
where
name like 'S%';
Toad will display this when I describe it later:
DROP VIEW XXX.TESTVIEWFORMATTING;
/* Formatted on 04.07.2012 09:35:45 (QP5 v5.185.11230.41888) */
CREATE OR REPLACE FORCE VIEW XXX.TESTVIEWFORMATTING
(
NAME,
ACCOUNTNUMBER
)
AS
select name, --This comment will be kept
accountnumber --This also
from debtable
where name like 'S%';
Note that the first comment has disappeared, and that the format is totally different.
I suspect that Oracle doesn't store the code of the view, just some parsed version, and when Toad brings up the script, it reverses this parsed version and generates a script on the fly.
What will I have to do to make Toad/Oracle keep the original formatting?
(PS: I know I can change the settings for Toad's code formatter, but this is not what I want to do. Due to some questionable choices in my past, this particular view has several levels of inline views, and I need a very specific formatting to make it clear what happens)
select text from user_views
where view_name = 'YOUR_VIEW_NAME';
I've tested with:
create view z_v_test as
select
-- te
--st
* from
dual;
and it keeps even the blank line.
Another way is to use DBMS_METADATA:
select dbms_metadata.get_ddl('VIEW', 'YOUR_VIEW_NAME', user) from dual
This works not only for views, but also for (nearly) all kind of database objects (tables, triggers, functions, ...).