I have failed to understand the need for pgScript, which could be executed using pgAdmin tool. When it should be used? What it can do that plpgSQL cannot do? What is equivalent of it in Microsoft SQL Server?
pgScript is a client-side scripting language, while pl/PgSQL runs on the server. This means they have entirely different use cases. For example, PgScript can manage transaction status while pl/PgSQL cannot, but pl/Pgsql can be used to extend the language of SQL while pgScript cannot do that.
Additionally it means the two will handle many other things quite differently ranging from query plans to dynamic SQL, and while pgScript requires round trips between queries pl/Pgsql does not.
One use for pgScript is to define variables and use them later in your SQLs.
For example, you could do something like this:
declare #mytbl, #maxid;
set #mytbl = 'sometable';
set #maxid = 2500;
set #res = select count(*) from #mytbl where id <= #maxid;
print #res;
This approach is to just have any variables you want to change at the top of your script, rather than those getting buried deep inside complex SQL queries.
Of course, pgScript is a feature available only inside PgAdmin III client like #{Craig Ringer} mentioned in his comment.
I used DDL script generator from Toad Data Modeler.
I ran the script using normal query execution in PgAdmin-III but it kept giving me error:
"ERROR: relation "user" already exists SQL state: 42P07".
I ran Execute pgScript in PgAdmin-III and it worked fine.
Related
When I try to use RAISE NOTICE in a Query tool in PgAdmin I just get "ERROR: syntax error at or near "RAISE"". This is stopping defining a stored procedure which uses RAISE NOTICE.
I have simply typed the following into a Query Tool window:
RAISE NOTICE 'Bob';
I am using PgAdmin 6.3 (the latest), just updated from v4.5 which had the same problem.
RAISE is part of pl/pgsql, Postgres's default procedural language. It is not available in a direct SQL context, or any function or stored procedure defined with LANGUAGE sql rather than LANGUAGE plpgsql.
If you're used to a different DBMS like MySQL or SQL Server, you might expect to have procedural code (variables, conditionals, loops, etc) available by default, but that's not how Postgres works. In order to use procedural code, you need to be inside a function, stored procedure, or DO statement.
When I'm sketching out SQL statements I have a file of all the queries I have used to analyse my live data. Each time I write a new statement or group of statements at the end of the fileI select them and click 'execute' to see the results. I'm paranoid that I may forget the selection stage and accidentally run all the queries sequentially in the entire file and so I head the file with the line
USE FakeDatabase
so that the queries will fail as they will be run against a non-existing database. But no, instead I get the error
USE statement is not supported to switch between databases
(N.B. I am using SQL Server Management Studio v17.0 RC1 against a v12 Azure SQL Server database.)
What tSQL statement can I use that will prevent further execution of tSQL statements in a file?
use is not supported in AZURE...you can try below ,but there can be many options depending on your use case
Replace use Database with below statement
if db_name() <>'Fakedatabase'
return;
You could, instead, put something like this in each script:
IF ##SERVERNAME <> 'Not-Really-My-Server'
BEGIN
raiserror('Database Name Not Set', 20, -1) with log
END
-- Rest of my query...
I'm studying the PREPARE and EXECUTE commands to optimize my functions in PostgreSQL, but i have some problems.
I have the following PREPARE command:
PREPARE my_query(int) AS SELECT id FROM table1 WHERE id = $1;
So, I need store this result (ID) into a variable, like this:
EXECUTE my_query(10) INTO var_1;
But I got a syntax error. What is the correct way to do this?
Your question doesn't really make any sense to me.
If you are trying to execute the prepared statement from within PL/PgSQL than you're out of luck. The EXECUTE command is reserved for a different purpose within PL/PgSQL. Not that it would have much use, PL/PgSQL plans are prepared and cached by default anyhow :)
If you are trying to do this outside of PL/PgSQL than the INTO would mean you are trying to write the result to a new table. Something you are unlikely to do/need that often.
I have the following MySQL script which I want to implement in PostgreSQL.
SET #statement = search_address_query;
PREPARE dynquery FROM #statement;
EXECUTE dynquery;
DEALLOCATE PREPARE dynquery;
How can I define user defined variable "#statement" using PostgreSQL.
Postgres does not normally use variables in plain SQL. But you can do that, too:
SET foo.test = 'SELECT bar FROM baz';
SELECT current_setting('foo.test');
Read about Customized Options in the manual.
In PostgreSQL 9.1 or earlier you needed to declare custom_variable_classes before you could use that.
However, You cannot EXECUTE dynamic SQL without a PL (procedural language). You would use a DO command for executing ad-hoc statements (but you cannot return data from it). Or use CREATE FUNCTION to create a function that executes dynamic SQL (and can return data in any fashion imaginable).
Be sure to safeguard against SQL injection when using dynamic SQL.
Related:
Is there a way to define a named constant in a PostgreSQL query?
Currently my development environment is using SQL server express 2008 r2 and VS2010 for my project development.
My question is like this by providing a scenario:
Development goal:
I develop window services something like data mining or data warehousing using .net C#.
That meant I have a two or more database involved.
my senario is like this:
I have a database with a table call SQL_Stored inside provided with a coloum name QueryToExec.
I first idea that get on my mind is written a stored procedure and i tried to came out a stored procedure name Extract_Sources with two parameter passed in thats ID and TableName.
My first step is to select out the sql need to be execute from table SQL_Stored. I tried to get the SQL by using a simple select statement such as:
Select Download_Sql As Query From SQL_Stored
Where ID=#ID AND TableName=#TableName
Is that possible to get the result or is there another way to do so?
My Second step is to excecute the Sql that i get from SQL_Stored Table.Is possible to
to execute the query that select on the following process of this particular stored proc?
Need to create a variable to store the sql ?
Thank you,Appreciate for you all help.Please don't hesitate to voice out my error or mistake because I can learn from it. Thank you.
PS_1:I am sorry for my poor English.
PS_2:I am new to stored procedure.
LiangCk
Try this:
DECLARE #download_sql VARCHAR(MAX)
Select
#download_sql = Download_Sql
From
SQL_Stored
Where
AreaID = #AreaID
AND TableName = #TableName
EXEC (#download_sql)