For example, I'd like to run:
REGEXP_REPLACE("What's My Name?", "[^a-z0-9_\-]", "-");
and simply see what it returns, instead of doing a search against a DB Table. I tried to run it in the CLI and got
ERROR: syntax error at or near "REGEXP_REPLACE"
LINE 1: REGEXP_REPLACE("What's My Name?", "[^a-z0-9_\-]", "-")
(I'm trying to be generic- I'd like to be able to use this for other PSQL Aggregate Functions as well.)
Remember, this is SQL, so every output you get is a relation. Hence to calculate the result of a function, you need to run SELECT to retrieve the function's value.
Unfortunately, in many DBs, SELECT requires a table. In Oracle land, there's dual to work around this problem:
SELECT REGEXP_REPLACE('What''s My Name?', '[^a-z0-9_\-]', '-') FROM dual;
PostgreSQL, however, allows you to execute a SELECT query without having to specify a table:
SELECT REGEXP_REPLACE('What''s My Name?', '[^a-z0-9_\-]', '-');
Note that the string quote in SQL is ', not ". PostgreSQL uses double quotes to quote identifiers.
Side note: Not every function is an aggregate. An aggregate is a function that combines multiple values into a single output value. REGEXP_REPLACE() is just a normal string function.
Is there a way to run a single PSQL Aggregate Function without hitting a database table?
Yes, in PostgreSQL you can write a SELECT statement without a FROM part at all.
Related
I have a Lookup that retrieves a few records from a MS SQL table containing schema, table name and a whole where clause. These values are passed to a copy data (within a ForEach) In the copy data i use a Dynamic query statement like:
#concat('select a.*, current_date as crt_tms from ',item().shm_nam,'.',item().tab_nam,
item().where_clause )
This construction works fine without the where_clause or with a where clause with an integer. But it goes wrong with strings like:
'a where a.CODSYSBRN ='XXX' ;'
it's about the quote (')
How can i pass it through?
I know that the where clause as a fixed string in the dynamic query works when i use double quotes (to escape the single quote):
'a where a.CODSYSBRN =''XXX'' ;'
Point is i need the where clause to be completely dynamic because it differ per table
whatever i try i get this kind of error:
Syntax error or access violation;257 sql syntax error: incorrect syntax near "where a"
ps i also tested this, but with the same result:
select a.*, current_date as crt_tms from #{item().shm_nam}.#{item().tab_nam} a #{item().where_clause}
As you have mentioned you are getting whole where clause from the lookup table, the query must have included the column values in where clause for string and integer types separately.
Example lookup table:
In your copy activity, you can use Concat() function as you were already doing it, to combine static values & parameters.
#concat('select * from ',item().schma_name,'.',item().table_name,' ',item().where_clause)
For debugging purposes, I have added the expression in set variable activity, to see the value of the expression.
Iteration1:
Iteration2:
I have the following string:
SELECT hello as "helloHello", '' as "empty" FROM tbl_test
I want to do something like this:
INSERT INTO tbl_x (a, b, c) VALUES (x, y, string_from_above)
The strings are going to be dynamic (basically they're strings of sql statements), so I do not want to escape all the ' and ". If I open the postgres database and double click on the varchar column, I can copy and paste the string and it goes in exactly as it looks. I want to be able to programmatically do so. Is there a way using an insert command? I tried using pgFormat, but that didn't work. See attached pic with what it looks like in the table.
All PostgreSQL APIs worth their money have a way to escape strings for inclusion in a dynamic SQL statement.
For example, if you write in C, you can use libpq's PQescapeLiteral().
There are also SQL functions for this: quote_literal() and format(). They can be used in PL/pgSQL code.
Don't try to write your own code for this. Use prior art and avoid the risk of getting it wrong.
I am trying to make workload test in Jmeter.
This is Postgresql and I would like to combine a random variable with '%'.
Could you help me the way to make sql query?
I have already tried with '?%', but there is an error "The column index is out of range: 1, number of columns: 0.".
The easiest way is switching to Select Statement and amend your query to look like:
SELECT * FROM scloud_usr.tcus_usr_rgn where UID like '${__RandomString(3,ABD,UID)}%'
If you want to continue with the Prepared Select Statement you need to add this % wildcard to the parameter value itself, not in the query, i.e.
More information:
Using “like” wildcard in prepared statement
Performance Testing BLOB from a MySQL Database with JMeter
Prepared statements with % wildcards
I'm trying to insert into a remote database using DBLink, and I'm making the query through Psycopg2. This is my code that takes a list of column names called fields and a list of column values called values:
fields_str = ",".join(fields)
values_str = ("%s, " * len(values))[:-2]
query = """SELECT dblink_exec('{0}', 'INSERT INTO {1} ({2}) VALUES ({3});'""".format(self.foreign_db,
table,
fields_str,
values_str)
This doesn't work because DBLink expects two single quotes around every string value like in the example in their documentation: SELECT dblink_exec('myconn', 'insert into foo values(21,''z'',''{"a0","b0","c0"}'');');
The problem is that Psycopg2 sticks an "E" in front of all my strings to escape them. That means neither adding single quotes around all my values nor adding single quotes around all my "%s" parts in my query can fix this. The general problem seems to be that Psycopg2 cannot properly handle escaping strings within a DBLink query string.
psycopg2.ProgrammingError: syntax error at or near "f5907160"
LINE 1: ...ar,tag,oid,objecttype,updatedat,usedat) VALUES (E'f5907160-4...
Any way around this?
I have written a DB2 query to do the following:
Create a temp table
Select from a monster query / insert into the temp table
Select from the temp table / delete from old table
Select from the temp table / insert into a different table
In MSSQL, I am allowed to run the commands one after another as one long query. Failing that, I can delimit them with 'GO' commands. When I attempt this in DB2, I get the error:
DB2CLI.DLL: ERROR [42601] [IBM][CLI Driver][DB2] SQL0199N The use of the reserved
word "GO" following "" is not valid. Expected tokens may include: "".
SQLSTATE=42601
What can I use to delimit these instructions without the temp table going out of scope?
GO is something that is used in MSSQL Studio, I have my own app for running upates into live and use "GO" to break the statements apart.
Does DB2 support the semi-colon (;)? This is a standard delimiter in many SQL implementations.
have you tried using just a semi-colon instead of "GO"?
This link suggests that the semi-colon should work for DB2 - http://www.scribd.com/doc/16640/IBM-DB2
I would try wrapping what you are looking to do in BEGIN and END to set the scope.
GO is not a SQL command, it's not even a TSQL command. It is an instruction for the parser. I don't know DB2, but I would imagine that GO is not neccessary.
From Devx.com Tips
Although GO is not a T-SQL statement, it is often used in T-SQL code and unless you know what it is it can be a mystery. So what is its purpose? Well, it causes all statements from the beginning of the script or the last GO statement (whichever is closer) to be compiled into one execution plan and sent to the server independent of any other batches.