Is there a way in T-SQL (SQL Server 2005) to assign a whole record to a record variable and then refer to the particular values using column names?
I mean, instead of:
select #var1 = col1,
#var2 = col2
from mytable
where ID = 1;
and referring to them as #var1 and #var2, something like
#record =
select col1, col2
from mytable
where ID = 1;
and referring to them like #record.col1 and #record.col2 .
I am beginner in t-sql, so hopefully the question is not too trivial.
You can create a table variable and select the whole resultset into it:
DECLARE #tt TABLE (col1 INT, col2 INT)
INSERT
INTO #tt
SELECT col1, col2
FROM mytable
WHERE id = 1
, but you cannot access its data except than in the SELECT query as well.
With pure TSQL (that it without custom datatypes) the thing you ask is impossible.
sounds like you are a programmer ... look at linq maybe as it does what you want.
You can use a temporary table and SELECT...INTO to avoid specifying the column names at the beginning :
SELECT Field1, Field2
INTO #TempTable
FROM MyTable
WHERE MyTable.MyID = 1
but of course you'll still need the FROM #TempTable part when referring to the column names.
SELECT Field1, Field2
FROM #TempTable
and of course to remember to drop the table at the end :
DROP #TempTable
The app code is where you'd normally refer to a single row at a time as a variable.
You could use XML, but you'd have to play with this...
DECLARE #MyRecord xml
DECLARE #Mytable TABLE (col1 int NOT NULL, col2 varchar(30) NOT NULL)
INSERT #Mytable (col1, col2) VALUES (1, 'bob')
select #MyRecord =
(SELECT *
from #Mytable
where col1 = 1
FOR XML AUTO)
SELECT #myRecord.value('./#col', 'int') --also #myRecord.value('#col', 'int')
--gives error
Msg 2390, Level 16, State 1, Line 12
XQuery [value()]: Top-level attribute nodes are not supported
Buried in the Transact SQL documentation I came across this restriction on variables:
Variables can be used only in expressions, not in place of object names or keywords.
Since you'd need to use an object name to qualify a column I don't believe that this is allowed.
Related
I am running a query similar to
DECLARE #VARIABLE NVARCHAR(50) = 'VALUE';
WITH MYCTE_TABLE (Column1,Column2)
AS
SELECT
(ColumnA, Column B
FROM
SomeTable
WHERE
ColumnA = SomeValue)
IF EXISTS(SELECT ColumnZ FROM AnotherTable WHERE Columnz = SomeNumbers)
BEGIN
SELECT * FROM MYCTE_TABLE
END
ELSE
BEGIN
MYSUBQUERY2
END
...
However, I keep getting the following error:
Incorrect syntax near the keyword 'IF'.
Each subquery works well when run independently. It seems the use of a common table expression before the IF EXISTS is causing the issue.
Any help please?
I really doubt, that this is the best approach... You tried to clean and shorten this for brevitiy (thumbs up for this!), but the given information is - maybe - not enough.
You cannot use a CTE in different queries. A CTE is fully inlined as part of the query...
But you could write your values into a table variable like here:
DECLARE #tbl TABLE(Column1 INT, Column2 VARCHAR(100)); --Choose appropriate types
INSERT INTO #tbl
SELECT ColumnA, ColumnB FROM SomeTable WHERE ColumnA=SomeValue;
This table variable can be used in later queries (but in the same job!) like any other table:
SELECT *
FROM SomeTable AS st
INNER JOIN #tbl AS tbl ON ...
... or similiar usages...
Another approach might be this
SELECT Column1,Column2 INTO #SomeTempTable FROM SomeWhere
This will write the result of the SELECT into a temp table (which is session wide).
I'm quite sure, that there might be a better (set-based) approach... Are the two sub-queries identical in their result set's structure? If so, you might use UNION ALL and place your "IF EXISTS" as a WHERE-clause to each sub query.
IF is control flow. WITH is within a query. You can do:
IF EXISTS (SELECT ColumnZ FROM AnotherTable WHERE Columnz=SomeNumbers)
BEGIN
WITH MYCTE_TABLE (Column1,Column2)AS
SELECT (ColumnA, Column B FROM SomeTable WHERE ColumnA=SomeValue)
MYSUBQUERY1
END;
ELSE
BEGIN
WITH MYCTE_TABLE (Column1,Column2)AS
SELECT (ColumnA, Column B FROM SomeTable WHERE ColumnA=SomeValue)
MYSUBQUERY2
END;
Or you could use a temporary table or table variable to store the values.
I have a list of values such as
1,2,3,4...
that will be passed into my SQL query.
I need to have these values stored in a table variable. So essentially I need something like this:
declare #t (num int)
insert into #t values (1),(2),(3),(4)...
Is it possible to do that formatting in SQL Server? (turning 1,2,3,4... into (1),(2),(3),(4)...
Note: I can not change what those values look like before they get to my SQL script; I'm stuck with that list. also it may not always be 4 values; it could 1 or more.
Edit to show what values look like: under normal circumstances, this is how it would work:
select t.pk
from a_table t
where t.pk in (#place_holder#)
#placeholder# is just a literal place holder. when some one would run the report, #placeholder# is replaced with the literal values from the filter of that report:
select t.pk
from a_table t
where t.pk in (1,2,3,4) -- or whatever the user selects
t.pk is an int
note: doing
declare #t as table (
num int
)
insert into #t values (#Placeholder#)
does not work.
Your description is a bit ridicuolus, but you might give this a try:
Whatever you mean with this
I see what your trying to say; but if I type out '#placeholder#' in the script, I'll end up with '1','2','3','4' and not '1,2,3,4'
I assume this is a string with numbers, each number between single qoutes, separated with a comma:
DECLARE #passedIn VARCHAR(100)='''1'',''2'',''3'',''4'',''5'',''6'',''7''';
SELECT #passedIn; -->: '1','2','3','4','5','6','7'
Now the variable #passedIn holds exactly what you are talking about
I'll use a dynamic SQL-Statement to insert this in a temp-table (declared table variable would not work here...)
CREATE TABLE #tmpTable(ID INT);
DECLARE #cmd VARCHAR(MAX)=
'INSERT INTO #tmpTable(ID) VALUES (' + REPLACE(SUBSTRING(#passedIn,2,LEN(#passedIn)-2),''',''','),(') + ');';
EXEC (#cmd);
SELECT * FROM #tmpTable;
GO
DROP TABLE #tmpTable;
UPDATE 1: no dynamic SQL necessary, all ad-hoc...
You can get the list of numbers as derived table in a CTE easily.
This can be used in a following statement like WHERE SomeID IN(SELECT ID FROM MyIDs) (similar to this: dynamic IN section )
WITH MyIDs(ID) AS
(
SELECT A.B.value('.','int') AS ID
FROM
(
SELECT CAST('<x>' + REPLACE(SUBSTRING(#passedIn,2,LEN(#passedIn)-2),''',''','</x><x>') + '</x>' AS XML) AS AsXml
) as tbl
CROSS APPLY tbl.AsXml.nodes('/x') AS A(B)
)
SELECT * FROM MyIDs
UPDATE 2:
And to answer your question exactly:
With this following the CTE
insert into #t(num)
SELECT ID FROM MyIDs
... you would actually get your declared table variable filled - if you need it later...
I want to get just schema of arbitrary sql query in SQL server.
For example-
Create Table Tabl1(Ta1bID int ,col1 varchar(10))
Create Table Tabl2(Tab1ID int ,col2 varchar(20))
SQL Query -
SELECT col1, col2
FROM Tab1
INNER JOIN Tab2 ON Tab1ID = Tab2ID
Here result will have this schema-
Col1 varchar(10), Col2 varchar(20)
I want to know what will be schema of result.
PS : I have just read access on the server where I am executing this query.
Any way to do this?
The schema, you mean to say datatype right? For resulted datatype will you always know when you operate on table(s). In your case both column is varchar datatype, so it will give character datatype, that you may convert into any character datatype like varchar, nvarchar, char, ntext etc.
Basic thing is, table designing was/is done by, so that time we know why we define datatype, now when you execute query below , you always know what will come with datatype of each column.
SELECT col1, col2
FROM Tab1
INNER JOIN Tab2 ON Tab1ID = Tab2ID
This though will issue when you use dynamic query, where you run time add column as per your requirement and you then execute which may or may not give error, due to mismatch of wrong datatype.
like
declare #sqlstring nvarchar(max)
set #sqlstring = 'declare #t table (name varchar(50))
insert into #t values(''Minh''),(''Tinh''),(''Justin'')
Select * from #t where Name like ''%in%'''
EXEC sp_executesql #sqlstring
I had similar problem before, but I had to create tables (70+) of each query one by one.
If there is a pattern, write a tool to generate create table
statement.
If not and it's one time job, just create them manually.
If it's not one time job, you might be thinking, why would store temp
date in table instead of temp table.
My table has a large number of columns. I have a command to copy some data - think of it as cloning a product - but as the columns may change in the future, I would like to only select everything from the table and only change the value of one column without having to refer to the rest.
Eg instead of:
INSERT INTO MYTABLE (
SELECT NEW_ID, COLUMN_1, COLUMN_2, COLUMN_3, etc
FROM MYTABLE)
I would like something resembling
INSERT INTO MYTABLE (
SELECT * {update this, set ID = NEW_ID}
FROM MYTABLE)
Is there a simple way to do this?
This is a DB2 database on an iSeries, but answers for any platform are welcome.
You could do this:
create table mytable_copy as select * from mytable;
update mytable_copy set id=new_id;
insert into mytable select * from mytable_copy;
drop table mytable_copy;
I don't think this is doable entirely within SQL without going to the trouble of creating a temp table. Doing it in memory should be much faster. Beware if you go the temporary table route that you must choose a unique name for your table for each function invocation to avoid the race condition where your code runs twice at the same time and mangles two rows of data into one temp table.
I don't know what kind of language you're using but it should be possible to obtain a list of fields in your program. I would do it like this:
array_of_field_names = conn->get_field__list;
array_of_row_values = conn->execute ("SELECT... ");
array_of_row_values ["ID"] = new_id_value
insert_query_string = "construct insert query string from list of field names and values";
conn->execute (insert_query_string);
Then you can encapsulate that as a function and just call it specifying table, old id and new id and it'd work it's magic.
In Perl code the following snippet would do:
$table_name = "MYTABLE";
$field_name = "ID";
$existing_field_value = "100";
$new_field_value = "101";
my $q = $dbh->prepare ("SELECT * FROM $table_name WHERE $field_name=?");
$q->execute ($existing_field_value);
my $rowdata = $q->fetchrow_hashref; # includes field names
$rowdata->{$field_name} = $new_field_value;
my $insq = $dbh->prepare ("INSERT INTO $table_name (" . join (", ", keys %$rowdata) .
") VALUES (" . join (", ", map { "?" } keys %$rowdata) . ");";
$insq->execute (values %$rowdata);
Hope this helps.
Ok, try this:
declare #othercols nvarchar(max);
declare #qry nvarchar(max);
select #othercols = (
select ', ' + quotename(name)
from sys.columns
where object_id = object_id('tableA')
and name <> 'Field3'
and is_identity = 0
for xml path(''));
select #qry = 'insert mynewtable (changingcol' + #othercols + ') select newval' + #othercols;
exec sp_executesql #qry;
Before you run the "sp_executesql" line, please do "select #qry" to see what the command is that you're going to run.
And of course, you may want to stick this in a stored procedure and pass in a variable instead of the 'Field3' bit.
Rob
Your example should almost work.
Just add the column names of the new table to it.
INSERT INTO MYTABLE
(id, col1, col2)
SELECT new_id,col1, col2
FROM TABLE2
WHERE ...;
i've never worked with db2 but in mssql you could solve it with following procedure. this solution only works if you dont care what new id the items get.
1.) create new table with same scheme but where the id column incrementes automatically. (mssql "identitity specification = 1, identity increment = 1)
2.) than a simple
insert into newTable(col1, col2, col3)
select (col1, col2, col3) from oldatable
should be enough, be sure not to include your id colum in the above statement
I have a rather weak understanding of any of oracle's more advanced functionality but this should I think be possible.
Say I have a table with the following schema:
MyTable
Id INTEGER,
Col1 VARCHAR2(100),
Col2 VARCHAR2(100)
I would like to write an sproc with the following
PROCEDURE InsertOrUpdateMyTable(p_id in integer, p_col1 in varcahr2, p_col2 in varchar2)
Which, in the case of an update will, if the value in p_col1, p_col2 is null will not overwrite Col1, Col2 respectively
So If I have a record:
id=123, Col1='ABC', Col2='DEF'
exec InsertOrUpdateMyTable(123, 'XYZ', '098'); --results in id=123, Col1='XYZ', Col2='098'
exec InsertOrUpdateMyTable(123, NULL, '098'); --results in id=123, Col1='ABC', Col2='098'
exec InsertOrUpdateMyTable(123, NULL, NULL); --results in id=123, Col1='ABC', Col2='DEF'
Is there any simple way of doing this without having multiple SQL statements?
I am thinking there might be a way to do this with the Merge statement though I am only mildly familiar with it.
EDIT:
Cade Roux bellow suggests using COALESCE which works great! Here are some examples of using the coalesce kewyord.
And here is the solution for my problem:
MERGE INTO MyTable mt
USING (SELECT 1 FROM DUAL) a
ON (mt.ID = p_id)
WHEN MATCHED THEN
UPDATE
SET mt.Col1 = coalesce(p_col1, mt.Col1), mt.Col2 = coalesce(p_col2, mt.Col2)
WHEN NOT MATCHED THEN
INSERT (ID, Col1, Col2)
VALUES (p_id, p_col1, p_col2);
Change the call or the update statement to use
nvl(newValue, oldValue)
for the new field value.
Using MERGE and COALESCE? Try this link for an example
with
SET a.Col1 = COALESCE(incoming.Col1, a.Col1)
,a.Col2 = COALESCE(incoming.Col2, a.Col2)