I have a SQLITE3 database wherein I have stored various columns. One column (cmd) in particular contains the full command line and associated parameters. Is there a way to extract just the first word in this column (just before the first space)? I am not interested in seeing the various parameters used, but do want to see the command issued.
Here's an example:
select cmd from log2 limit 3;
user-sync //depot/PATH/interface.h
user-info
user-changes -s submitted //depot/PATH/build/...#2011/12/06:18:31:10,#2012/01/18:00:05:55
From the result above, I'd like to use an inline SQL function (if available in SQLITE3) to parse on the first instance of space, and perhaps use a left function call (I know this is not available in SQLITE3) to return just the "user-sync" string. Same for "user-info" and "user-changes".
Any ideas?
Thanks.
My soluion:
sqlite> CREATE TABLE command (cmd TEXT);
sqlite> INSERT INTO command (cmd) VALUES ('ls'),('cd ~'),(' mpv movie.mkv ');
sqlite> SELECT substr(trim(cmd),1,instr(trim(cmd)||' ',' ')-1) FROM command;
ls
cd
mpv
Pros:
it's not that a dirty hack
it only uses core functions
"Finds the first occurrence" function is one of the SQLite3 Core Functions (http://www.sqlite.org/lang_corefunc.html).
Of course, it is much better to use instr(X,Y).
So you can write:
SELECT substr(cmd,1,instr(cmd,' ')-1) FROM log2
As the position of your first space character is unknown, I don't think there is a corefunction in SQLite that will help.
I think you'll have to create one http://www.sqlite.org/c3ref/create_function.html
Here's a hack
sqlite> create table test (a);
sqlite> insert into test values ("This is a test.");
sqlite> select * from test;
This is a test.
sqlite> select rtrim(substr(replace(a,' ','----------------------------------------------------------------------------------------'),1,80),'-') from test;
This
It works as long as your longest command is less than 80 characters (and you include 80 '-' characters in the substitution string -- I didn't count them!). If your commands can contain '-' just use a different character that is not allowed in the commands.
I don't believe that's something you'll be able to do within the SQL itself. SQLite's support for string handling functions is not as extensive as other RDBMSs (some of which would let you do a SUBSTR with a Reg Exp).
My suggestion is either to write your own SQL function as suggested by #Jon or just do it as a post-processing step in your app code.
Related
I need to use cast function with length of column in teradata.
say I have a table with following data ,
id | name
1|dhawal
2|bhaskar
I need to use cast operation something like
select cast(name as CHAR(<length of column>) from table
how can i do that?
thanks
Dhawal
You have to find the length by looking at the table definition - either manually (show table) or by writing dynamic SQL that queries dbc.ColumnsV.
update
You can find the maximum length of the actual data using
select max(length(cast(... as varchar(<large enough value>))) from TABLE
But if this is for FastExport I think casting as varchar(large-enough-value) and postprocessing to remove the 2-byte length info FastExport includes is a better solution (since exporting a CHAR() will results in a fixed-length output file with lots of spaces in it).
You may know this already, but just in case: Teradata usually recommends switching to TPT instead of the legacy fexp.
I have the following problem and I'm begging for help: I'm using swi-prolog and odbc interface to connect to postgresql database. Problem occurs when I try to insert in database. SELECT works fine but INSERT doesn't work. Does anybody know what am I doing wrong.
Here's my simple test code:
:-use_module(library(odbc)).
connect(C):-
odbc_connect(baza, C, [user(Mat),
password(lozinka), alias(baza), open(once)]).
sel(R) :-
odbc_query(baza,
'SELECT * FROM pacijent',
R).
ins:-
odbc_query(baza, 'INSERT INTO pacijent (name, surname, passw, number) VALUES ("James", "Bond", 007, 007)').
This is the error when i try to insert:
?- ins.
ERROR: ODBC: State S1000: [unixODBC]ERROR: column "James" does not exist at character 30;
Error while executing the query
Also i tried to insert through psql console and everything works fine, but as said problem is when inserting from prolog.
Please help, im stuck here.
Thanks
A suggestion: proper escaping, don't know if it'll be enough though. I'd turn
"James", "Bond"
into
\'James\', \'Bond\'
The problem is you've passed the column data for columns name and surname in double quotes instead of single quotes. Most databases use " (double quotes) for identifiers like table and column names and ' (single quotes) for data. How you ensure that in prolog I don't know.
I suspect you'll want to quote the other 2 columns as well.
In ODBC you'd use SQLGetInfo and get SQL_IDENTIFIER_QUOTE_CHAR which will usually return double quotes meaning to quote identifiers use these quotes.
I have this SQLite table:
create table mytable (
aid INTEGER NOT NULL PRIMARY KEY,
bid INTEGER NOT NULL,
image BLOB
);
And I want to insert a binary file into the image field in this table. Is it possible to do it from the sqlite3 command line interface? If so, how? I'm using Ubuntu.
Thank you!
The sqlite3 command line interface adds the following two “application-defined” functions:
readfile
which typically is used as: INSERT INTO table(blob) VALUES (readfile('myimage.jpg'))
writefile
which writes a file with the contents of a database blob and returns the count of bytes written.
You may use a syntax like :
echo "insert into mytable values(1,1, \"`cat image`\")" | sqlite3 yourDb
i'm not sure for the " around blob's value. Note the backquotes around cat command, means the cat command will be executed before the echo.
[EDIT]
Blob are stored as hexa digit with "X" prefix. You can use "hexdump" unix command to produce the hexa string, but it would be better to write a command line tool that read image and do the insert.
More details on this post : http://comments.gmane.org/gmane.comp.db.sqlite.general/64149
I am using a sqlite database.
I want to excute sqlite from dos command line and insert fields into the tables by passing them as parameters from command line.
C:\run.bat name surname
want to create the run.bat file ...
sqlite > INSERT into tab(col1, col2) Values (%1,%2);
I guess you're looking for something like this:
sqlite3 DATABASENAME 'insert into dbo.TABLE values('%1', '%2')'
You'll need the command line program sqlite3.exe. Then you can put into your batch file:
sqlite3 dbname "INSERT INTO TableName (ColName1, ColName2) VALUES (%1, %2);"
Also note that you will have to be aware of the datatypes of the columns and, if the VALUES for those datatypes require quoting, you'll need to add the quotes into the command line (and handle embedded quotes in the values, if that's a possible occurence).
How can I insert special symbols like trademark into SQLite table? I have tried to use PRAGMA encoding = "UTF-16" with no effect :(
Typically if you surround an SQL entry with ''Single quotes, it goes in as a literal.
i.e.
'™'
problem solved. it is necessary to open DB file with sqlite3_open16, then execute command PRAGMA encoding = \"UTF-16\"; (I am not sure, if it is necessary). Now the insert will be done with UTF-16.
To select from db (to get column value) is necessary to use sqlite3_column_text16 function