What is the equivalent of the Oracle "Dual" table in MS SqlServer? - sql

What is the equivalent of the Oracle "Dual" table in MS SqlServer?
This is my Select:
SELECT pCliente,
'xxx.x.xxx.xx' AS Servidor,
xxxx AS Extension,
xxxx AS Grupo,
xxxx AS Puerto
FROM DUAL;

In sql-server, there is no dual you can simply do
SELECT pCliente,
'xxx.x.xxx.xx' AS Servidor,
xxxx AS Extension,
xxxx AS Grupo,
xxxx AS Puerto
However, if your problem is because you transfered some code from Oracle which reference to dual you can re-create the table :
CREATE TABLE DUAL
(
DUMMY VARCHAR(1)
)
GO
INSERT INTO DUAL (DUMMY)
VALUES ('X')
GO

You don't need DUAL in MSSQLserver
in oracle
select 'sample' from dual
is equal to
SELECT 'sample'
in sql server

While you usually don't need a DUAL table in SQL Server as explained by Jean-François Savard, I have needed to emulate DUAL for syntactic reasons in the past. Here are three options:
Create a DUAL table or view
-- A table
SELECT 'X' AS DUMMY INTO DUAL;
-- A view
CREATE VIEW DUAL AS SELECT 'X' AS DUMMY;
Once created, you can use it just as in Oracle.
Use a common table expression or a derived table
If you just need DUAL for the scope of a single query, this might do as well:
-- Common table expression
WITH DUAL(DUMMY) AS (SELECT 'X')
SELECT * FROM DUAL
-- Derived table
SELECT *
FROM (
SELECT 'X'
) DUAL(DUMMY)

In SQL Server there is no dual table. If you want to put a WHERE clause, you can simple put it directly like this:
SELECT 123 WHERE 1<2
I think in MySQL and Oracle they need a FROM clause to use a WHERE clause.
SELECT 123 FROM DUAL WHERE 1<2

This could be of some help I guess, when you need to join some tables based on local variables and get the information from those tables:
Note: Local variables must have been
Select #XCode as 'XCode '
,#XID as 'XID '
,x.XName as 'XName '
,#YCode as 'YCode '
,#YID as 'YID '
,y.YName as 'YName '
From (Select 1 as tst) t
Inner join Xtab x on x.XID = #XID
Inner join Ytab y on y.YID = #YID

It's much simpler than that.
Use literal values to establish data types.
Put quotes around column names if they need special characters.
Skip the WHERE clause if you need 1 row of data:
SELECT 'XCode' AS XCode
,1 AS XID
,'XName' AS "X Name"
,'YCode' AS YCode
,getDate() AS YID
,'YName' AS "Your Name"
WHERE 1 = 0

Related

Find value that is not a number or a predefined string

I have to test a column of a sql table for invalid values and for NULL.
Valid values are: Any number and the string 'n.v.' (with and without the dots and in every possible combination as listed in my sql command)
So far, I've tried this:
select count(*)
from table1
where column1 is null
or not REGEXP_LIKE(column1, '^[0-9,nv,Nv,nV,NV,n.v,N.v,n.V,N.V]+$');
The regular expression also matches the single character values 'n','N','v','V' (with and without a following dot). This shouldn't be the case, because I only want the exact character combinations as written in the sql command to be matched. I guess the problem has to do with using REGEXP_LIKE. Any ideas?
I guess this regexp will work:
NOT REGEXP_LIKE(column1, '^([0-9]+|n\.?v\.?)$', 'i')
Note that , is not a separator, . means any character, \. means the dot character itself and 'i' flag could be used to ignore case instead of hard coding all combinations of upper and lower case characters.
No need to use regexp (performance will increase by large data) - plain old TRANSLATE is good enough for your validation.
Note that the first translate(column1,'x0123456789','x') remove all numeric charcters from the string, so if you end with nullthe string is OK.
The second translate(lower(column1),'x.','x') removes all dots from the lowered string so you expect the result nv.
To avoid cases as n.....v.... you also limit the string length.
select
column1,
case when
translate(column1,'x0123456789','x') is null or /* numeric string */
translate(lower(column1),'x.','x') = 'nv' and length(column1) <= 4 then 'OK'
end as status
from table1
COLUMN1 STATUS
--------- ------
1010101 OK
1012828n
1012828nv
n.....v....
n.V OK
Test data
create table table1 as
select '1010101' column1 from dual union all -- OK numbers
select '1012828n' from dual union all -- invalid
select '1012828nv' from dual union all -- invalid
select 'n.....v....' from dual union all -- invalid
select 'n.V' from dual; -- OK nv
You can use:
select count(*)
from table1
WHERE TRANSLATE(column1, ' 0123456789', ' ') IS NULL
OR LOWER(column1) IN ('nv', 'n.v', 'nv.', 'n.v.');
Which, for the sample data:
CREATE TABLE table1 (column1) AS
SELECT '12345' FROM DUAL UNION ALL
SELECT 'nv' FROM DUAL UNION ALL
SELECT 'NV' FROM DUAL UNION ALL
SELECT 'nV' FROM DUAL UNION ALL
SELECT 'n.V.' FROM DUAL UNION ALL
SELECT '...................n.V.....................' FROM DUAL UNION ALL
SELECT '..nV' FROM DUAL UNION ALL
SELECT 'n..V' FROM DUAL UNION ALL
SELECT 'nV..' FROM DUAL UNION ALL
SELECT 'xyz' FROM DUAL UNION ALL
SELECT '123nv' FROM DUAL;
Outputs:
COUNT(*)
5
or, if you want any quantity of . then:
select count(*)
from table1
WHERE TRANSLATE(column1, ' 0123456789', ' ') IS NULL
OR REPLACE(LOWER(column1), '.') = 'nv';
Which outputs:
COUNT(*)
9
db<>fiddle here

How to extract the table name from a CREATE/UPDATE/INSERT statement in an SQL query?

I am trying to parse the table being created, inserted into or updated from the following sql queries stored in a table column.
Let's call the table column query. Following is some sample data to demonstrate variations in how the data could look like.
with sample_data as (
select 1 as id, 'CREATE TABLE tbl1 ...' as query union all
select 2 as id, 'CREATE OR REPLACE TABLE tbl1 ...' as query union all
select 3 as id, 'DROP TABLE IF EXISTS tbl1; CREATE TABLE tbl1 ...' as query union all
select 4 as id, 'INSERT /*some comment*/ INTO tbl2 ...' as query union all
select 5 as id, 'INSERT /*some comment*/ INTO tbl2 ...' as query union all
select 6 as id, 'UPDATE tbl3 SET col1 = ...' as query union all
select 7 as id, '/*some garbage comments*/ UPDATE tbl3 SET col1 = ...' as query union all
select 8 as id, 'DELETE tbl4 ...' as query
),
Following are the formats of the queries (we are trying to extract table_name ):
#1
some optional statements like drop table
CREATE some comments or optional statement like OR REPLACE TABLE table_name
everything else
#2
some optional statements like drop table
INSERT some comments INTO some comments table_name
#3
some optional statements like drop table
UPDATE some comments table_name
everything else
Regular Expression
To construct a suitable regex, let's start with the following relatively simple/readable version:
((CREATE( OR REPLACE)?|DROP) TABLE( IF EXISTS)?|UPDATE|DELETE|INSERT INTO) ([^\s\/*]+)
All the spaces above could be replaced with "at least one whitespace character", i.e. \s+. But we also need to allow comments. For a comment that looks like /*anything*/ the regex looks like \/\*.*\*\/ (where the comment characters are escaped with \ and "anything" is the .* in the middle). Given there could be multiple such comments, optionally separated by whitespace, we end up with (\s*\/\*.*\*\/\s*?)*\s+. Plugging this in everywhere there was a space gives:
((CREATE((\s*\/\*.*\*\/\s*?)*\s+OR(\s*\/\*.*\*\/\s*?)*\s+REPLACE)?|DROP)(\s*\/\*.*\*\/\s*?)*\s+TABLE((\s*\/\*.*\*\/\s*?)*\s+IF(\s*\/\*.*\*\/\s*?)*\s+EXISTS)?|UPDATE|DELETE|INSERT(\s*\/\*.*\*\/\s*?)*\s+INTO)(\s*\/\*.*\*\/\s*?)*\s+([^\s\/*]+)
One further refinement needs to be made: Bracketed expressions have been used for choices, e.g. (CHOICE1|CHOICE2). But this syntax includes them as capturing groups. Actually we only require one capturing group for the table name so we can exclude all the other capturing groups via ?:, e.g. (?:CHOICE1|CHOICE2). This gives:
(?:(?:CREATE(?:(?:\s*\/\*.*\*\/\s*?)*\s+OR(?:\s*\/\*.*\*\/\s*?)*\s+REPLACE)?|DROP)(?:\s*\/\*.*\*\/\s*?)*\s+TABLE(?:(?:\s*\/\*.*\*\/\s*?)*\s+IF(?:\s*\/\*.*\*\/\s*?)*\s+EXISTS)?|UPDATE|DELETE|INSERT(?:\s*\/\*.*\*\/\s*?)*\s+INTO)(?:\s*\/\*.*\*\/\s*?)*\s+([^\s\/*]+)
Online Regex Demo
Here's a demo of it working with your examples: Regex101 demo
SQL
The Google BigQuery documentation for REGEXP_EXTRACT says it will return the substring matched by the capturing group. So I'd expect something like this to work:
with sample_data as (
select 1 as id, 'CREATE TABLE tbl1 ...' as query union all
select 2 as id, 'CREATE OR REPLACE TABLE tbl1 ...' as query union all
select 3 as id, 'DROP TABLE IF EXISTS tbl1; CREATE TABLE tbl1 ...' as query union all
select 4 as id, 'INSERT /*some comment*/ INTO tbl2 ...' as query union all
select 5 as id, 'INSERT /*some comment*/ INTO tbl2 ...' as query union all
select 6 as id, 'UPDATE tbl3 SET col1 = ...' as query union all
select 7 as id, '/*some garbage comments*/ UPDATE tbl3 SET col1 = ...' as query union all
select 8 as id, 'DELETE tbl4 ...' as query
)
SELECT
*, REGEXP_EXTRACT(query, r"(?:(?:CREATE(?:(?:\s*\/\*.*\*\/\s*?)*\s+OR(?:\s*\/\*.*\*\/\s*?)*\s+REPLACE)?|DROP)(?:\s*\/\*.*\*\/\s*?)*\s+TABLE(?:(?:\s*\/\*.*\*\/\s*?)*\s+IF(?:\s*\/\*.*\*\/\s*?)*\s+EXISTS)?|UPDATE|DELETE|INSERT(?:\s*\/\*.*\*\/\s*?)*\s+INTO)(?:\s*\/\*.*\*\/\s*?)*\s+([^\s\/*]+)") AS table_name
FROM sample_data;
(The above is untested so please let me know in the comments if there are any issues.)
I think it really depends on your data, but you might find some success using an approach like this:
with data as (
select 1 as id, 'CREATE TABLE tbl1 ...' as query union all
select 2 as id, 'INSERT INTO tbl2 ...' as query union all
select 3 as id, 'UPDATE tbl3 ...' as query union all
select 4 as id, 'DELETE tbl4 ...' as query
),
splitted as (
select id, split(query, ' ') as query_parts from data
)
select
id,
case
when query_parts[safe_offset(0)] in('CREATE', 'INSERT') then query_parts[safe_offset(2)]
when query_parts[safe_offset(0)] in('UPDATE', 'DELETE') then query_parts[safe_offset(1)]
else 'Error'
end as table_name
from splitted
Of course this depends on the cleanliness and syntax in your query column. Also, if your table_name is qualified with project.table.dataset you would need to do further splitting.

How to cut everything after a specific character, but in case string doesn't contain it do nothing?

Let's say i have following data:
fjflka, kdjf
ssssllkjf fkdsjl
skfjjsld, kjl
jdkfjlj, ksd
lkjlkj hjk
I want to cut out everything after ',' but in case the string doesn't contain this character, it wont do anything, if i use substr and cut everything after ',' the string which doesn't contain this character shows as null. How do i achieve this? Im using oracle 11g.
This should work. Simply use regexp_substr
with t_view as (
select 'fjflka, kdjf' as text from dual union
select 'ssssllkjf fkdsjl' from dual union
select 'skfjjsld, kjl' from dual union
select 'jdkfjlj, ksd' from dual union
select 'lkjlkj hjk' from dual
)
select text,regexp_substr(text,'[^,]+',1,1) from t_view;
Assuming your table :
SQL> desc mytable
s varchar2(100)
you may use:
select decode(instr(s,','),0,s,substr(s,1,instr(s,',')-1)) from mytable;
demo
Well the below query works as per your requirement.
with mytable as
(select 'aaasfasf wqwe' s from dual
union all
select 'aaasfasf, wqwe' s from dual)
select s,substr(s||',',1,instr(s||',',',')-1) from mytable;

How to define temporary table values in a subquery in Oracle

I am approaching this issue from a non DBA perspective, as in I do not have permissions to create new tables for the database. I am trying to work around this by using a subquery in Oracle kind of like this sudo code:
With temptable as ('col1name', 'col2name', 1,'a',2,'b')
Select * from temptable where col1name = 1
With the temptable looking like
Col1name | Col2name
1 a
2 b
And the output being row 1. I know it is not the easiest way to do it, but it is all I can think of to accomplish my task until I can get the admin to approve a new table. I have searched a lot but I can't find an answer. Is there a simple way to define temporary table data like this?
I would just do this as:
with temptable as (
select 1 as col1name, 'a' col2name from dual union all
select 2, 'b' from dual
)
Select *
from temptable
where col1name = 1;
As an alternative to a CTE (common table expresssion) as suggested by Gordon, you can also use a query as an old-school inline view.
For example:
SELECT tt.col1name
, tt.col2name
FROM ( SELECT 1 AS col1name, 'a' AS col2name FROM DUAL
UNION ALL SELECT 2, 'b' FROM DUAL
UNION ALL SELECT 3, 'c' FROM DUAL
) tt
WHERE tt.col1name = 1
ORDER
BY tt.col1name

select statement with subqueries against two databases

I have the below code to show what I am "trying" to accomplish in a stored procedure:
select * from
(
select to_char(sum(aa.amount))
from additional_amount aa, status st
where aa.int_tran_id = st.int_tran_id
and st.stage in ('ACHPayment_Confirmed')
and aa.entry_timestamp > (
select to_date(trunc(last_day(add_months(sysdate,-1))+1), 'DD-MON-RR') AS "day 1"
from dual
)
)
UNION ALL
(
select distinct it.debit_acct as "debit_accounts"
from internal_transactions it
where it.debit_acct IN ( select texe_cnasupro
from service.kndtexe, service.kndtctc
where texe_cncclipu = tctc_cncclipu
and tctc_cntipcli = 'C'
)
)
union all
(select distinct it.credit_acct as "credit_account"
from internal_transactions it
where it.credit_acct IN (select texe_cnasupro
from service.kndtexe, service.kndtctc
where texe_cncclipu = tctc_cncclipu
and tctc_cntipcli = 'C'
)
)
;
Output:
TO_CHAR(SUM(AA.AMOUNT))
----------------------------------------
130250292.22
6710654504
0000050334
2535814905
0007049560
5 rows selected
The top row of the output is what I need in the SP as output based on the below two queries which I am guessing needs to be sub-queried against the top select statement.
The top select is to select the sum of the amount a table with a join against another table for filtering (output:130250292.22).
The second and third selects is actually to check that the accounts in the internal_transactions table are signed up for the corresponding two tables in the service db which is a different db on the same server(owned by the same application).
The tables in the "service" db do not have the same common primary keys as in the first select which is against the same database.
Thank you for your help!
I don't understand your question, but I do know you can simplify this bit:
to_date(trunc(last_day(add_months(sysdate,-1))+1), 'DD-MON-RR') AS "day 1"
to this
trunc (sysdate, 'mm')
and you don't need a SELECT from DUAL to do that either.
and aa.entry_timestamp > trunc (sysdate, 'mm')