I am using Delphi 7, BDE, and Interbase (testing), Oracle (Production).
I have two tables (Master, Responses)
I need to step through the Responses table, use its Master_Id field to look it up in Master table (id) for matching record and update a date field in the Master table with a date field in the Responses table
Can this be done in SQL, or do i actually have to create two TTables or TQueries and step through each record?
Example:
Open two tables (Table1, Table2)
with Table1 do
begin
first;
while not EOF do
begin
//get master_id field
//locate in id field in table 2
//edit record in table 2
next;
end;
end;
thanks
One slight modification to Chris' query, throw in a where clause to select only the records that need the update. Otherwise it will set the rest of the dates to NULL
UPDATE Master m
SET
m.date = (SELECT r.date FROM Reponses r WHERE r.master_id = m.id)
WHERE m.id IN (SELECT master_id FROM Responses)
Updated to use aliases to avoid confusion which col comes from which table.
This is not ready made, copy-past'able query as UPDATE syntax differs from database to database.
You may need to consult your database sql reference for JOIN in UPDATE statement syntax.
When there are multiple responses to same master entry
UPDATE Master m
SET m.date = (
SELECT MAX(r.date) FROM Reponses r WHERE r.master_id = m.id)
WHERE m.id IN (SELECT master_id FROM Responses)
I used MAX() you can use whatever suits your business.
Again invest some time understanding SQL. Its hardly a few days effort. Get PLSQL Complete reference if you are into Oracle
Try this SQL (changing names to fit your situation)
UPDATE Master m
SET date = ( SELECT date FROM Responses WHERE id = m.id )
Related
I have a group of enitities which need to have another record associated with them from another table.
When I try to output an Id for the table to be matched on it doesn't work because you can only output from inserted, updated etc.
DECLARE #SignatureGlobalIdsTbl table (ID int,
CompanyBankAccountId int);
INSERT INTO GlobalIds (TypeId)
-- I Cannot output cba.Id into the table since its not from inserted
OUTPUT Inserted.Id,
cba.Id
INTO #SignatureGlobalIdsTbl (ID,
CompanyBankAccountId)
SELECT (#DocumentsGlobalTypeKey)
FROM CompanyBankAccounts cba
INNER JOIN Companies c ON c.CompanyId = cba.CompanyId
WHERE SignatureDocumentId IS NULL
AND (SignatureFile IS NOT NULL
AND SignatureFile != '');
INSERT INTO Documents (DocumentPath,
DocumentType,
DocumentIsExternal,
OwnerGlobalId,
OwnerGlobalTypeID,
DocumentName,
Extension,
GlobalId)
SELECT SignatureFile,
#SignatureDocumentTypeKey,
1,
CompanyGlobalId,
#OwnerGlobalTypeKey,
[dbo].[fnGetFileNameWithoutExtension](SignatureFile),
[dbo].[fnGetFileExtension](SignatureFile),
documentGlobalId
FROM (SELECT c.GlobalId AS CompanyGlobalId,
cba.*,
s.ID AS documentGlobalId
FROM CompanyBankAccounts cba
INNER JOIN Companies c ON c.CompanyId = cba.CompanyId
CROSS JOIN #SignatureGlobalIdsTbl s) info
WHERE SignatureDocumentId IS NULL
AND (SignatureFile IS NOT NULL
AND SignatureFile != '');
I Tried to use cross join to prevent cartesian production but that did not work. I also tried to output the rownumber over some value but I could not get that to be stored in the table either.
If I have two seperate queries which return the same amount of records, how can I pair the records together without creating cartesian production?
'When I try to output an Id for the table ... it doesn't work.'
This seems to be because one of the columns you want to OUTPUT is not actually part of the insert. It's an annoying problem and I wish SQL Server would allow us to do it.
Someone may have a much better answer for this than I do, but the way I usually approach this is
Create a temporary table/etc of the data I want to insert, with a column for ID (starts blank)
Do an insert of the correct amount of rows, and get the IDs out into another temporary table,
Assign the IDs as appropriate within the original temporary table
Go back and update the inserted rows with any additional data needed (though that's probably not needed here given you're just inserting a constant)
What this does is to flag/get the IDs ready for you to use, then you allocate them to your data as needed, then fill in the table with the data. It's relatively simple although it does do 2 table hits rather than 1.
Also consider doing it all within a transaction to keep the data consistent (though also probably not needed here).
How can I pair the records together?
A cross join unfortunately multiplies the rows (number of rows on left times the number of rows on the right). It is useful in some instances, but possibly not here.
I suggest when you do your inserts above, you get an identifier (e.g., companyID) in your temp table and join on that.
If you don't have a matching record and just want to assign them in order, you can use an answer similar to my answer in another recent question How to update multiple rows in a temp table with multiple values from another table using only one ID common between them?
Further notes
I suggest avoiding table variables (e.g., DECLARE #yourtable TABLE) and use temporary tables (CREATE TABLE #yourtable) instead - for performance reasons. If it's only a small amount of rows it's OK, but it gets worse as it gets larger as SQL Server assumed that table variables only have 1 row
In your bottom statement, why is there the SELECT statement in the FROM clause? Couldn't you just get rid of that select statement and have the FROM clause list the tables you want?
I figured out a way to have access to the output, by using a merge statement.
DECLARE #LogoGlobalIdsTbl TABLE (ID INT, companyBankAccountID INT)
MERGE GlobalIds
USING
(
SELECT (cba.CompanyBankAccountId)
FROM CompanyBankAccounts cba
INNER JOIN Companies c on c.CompanyId = cba.CompanyId
WHERE cba.LogoDocumentId IS NULL AND (cba.LogoFile IS NOT NUll AND cba.LogoFile != '')
) src ON (1=0)
WHEN NOT MATCHED
THEN INSERT ( TypeId )
VALUES (#DocumentsGlobalTypeKey)
OUTPUT [INSERTED].[Id], src.CompanyBankAccountId
INTO #LogoGlobalIdsTbl;
I need to write an update statement for a table of mine.
The table contains a technical key and a customer ID.
I need to update a field in this table by raising the field with +1, but only for the fields where the technical key is at the max value for that specific customer ID.
At first I tried to write this with how I usually do it on MSSQL:
UPDATE a
SET a.VERSION_CHECK = (a.VERSION + 1)
FROM customers a
WHERE a.technical_key = (SELECT MAX(b.technical_key)
FROM customers b
WHERE a.customer_id = b.customer_id
)
I've since been trying to work with a WHERE EXISTS clause in the syntax of the SQL used in Oracle, but I can't seem to figure out how to work the MAX technical key in there correctly, so that only those rows are updated in the table. Anyone got any input please?
You can use a use a correlated subquery:
UPDATE customer c
SET VERSION_CHECK = VERSION + 1
WHERE c.technical_key = (SELECT MAX(c2.technical_key)
FROM customers c2
WHERE c2.customer_id = c.customer_id);
I have two tables #mtss table:
#mtss
( [MM],[YYYY],[month_Start],[month_Finish],[ProjectID],[ProjectedBillable],[ProjectedPayable],[ActualBilled],[ActualPaid],[Total_To_Bill],[Total_To_Pay])
tbl_Snapshot ([MM],[YYYY],[month_Start],[month_Finish],[ProjectID],[ProjectedBillable],[ProjectedPayable],[ActualBilled],[ActualPaid],[Total_To_Bill],[Total_To_Pay]
)
I need to compare two tables and find matches
if tbl_snapshot [MM] and [ProjectId] matches then delete record in tbl_snapshot and insert record from #mtts.
Thanks in advance.
Since you're on 2008, you can use MERGE to perform the as a single logical operation:
;merge into tbl_Snapshot s
using #mtss m on s.MM = m.MM and s.ProjectId = m.ProjectId
when matched then update
set
YYYY = m.YYYY,
month_Start = m.month_Start
/* Other columns as well, not going to type them all out */
;
This would also easily extend to other cases you may have to deal with, if the data only exists in one table and not the other, with addition match clauses.
Of course, thinking further, in this case a simple UPDATE would work also. A DELETE followed by an INSERT (where the deleted and inserted rows are related by a key) is the equivalent of an UPDATE.
Somethig like:
DELETE tbl_snapshot
FROM tbl_snapshot ss
INNER JOIN #mtss m ON m.MM = ss.MM AND m.ProjectId = ss.ProjectId
(I wrote the code directly to this editor so it might have errors, but it should give you an idea how to continue)
I made a copy of an existing table like this:
select * into table_copy from table
Since then I've made some schema changes to table (added/removed columns, changed order of columns etc). Now I need to run an update statement to populate a new column I added like this:
update t
set t.SomeNewColumn = copy.SomeOldColumn
from t
However, how do I get the second table in here based on row index instead of some column value matching up?
Note: Both tables still have equal number of rows in their original positions.
You cannot join the tables without a key to define each row uniquely, the position of the data in the table has no bearing on the situation.
If you tables do not have a primary key you need to define one.
If you have an ID on it, you can do this:
update t set
t.SomeNewColumn = copy.SomeOldColumn
from
table t
inner join table_copy copy on
t.id = copy.id
If you have no way to uniquely identify the row and are relying on the order of the rows, you're out of luck, as row order is not reliable in any version of SQL Server (nor most other RDBMSes).
You could use this to update them by matching ids
UPDATE
t
SET
t.SomeNewColumn = other_table.SomeOldColumn,
FROM
original_table t
INNER JOIN
other_table copy
ON
t.id = copy.id
or if you don't have the ids you might be able to pull out something by using ROW_NUMBER function to enumerate the records, but that's a long shot(I haven't checked if it's possible).
If you're updating, you'll need a primary key to join on. Usually in that case, the others' answers will suffice. If for some reason you still need to update the table with a resultset in a certain order, you can do this:
UPDATE t SET t.SomeNewColumn = copy.SomeOldColumn
FROM table t
JOIN (SELECT ROW_NUMBER() OVER(ORDER BY id) AS row, id, SomeNewColumn FROM table) t2
ON t2.Id = t.Id
JOIN (SELECT ROW_NUMBER() OVER(ORDER BY id) AS row, SomeOldColumn FROM copytable) copy
ON copy.row = t2.row
You get the new table and its row numbers in the order you want, join the old table and its row numbers in the order you want, and join back to the new table so the query has something to directly update.
I have a spreadsheet that I am converting to an Access DB. I have a column of typed out customer names that I want to replace with the appropriate customer number from our accounting system.
I have created a table with the customer info, and a query that shows what ID needs to be inserted into the source data. What I'm looking for is:
UPDATE tblStarting_Data
SET CustomerID=x
WHERE TEMPCustomer=y
Where X and Y come from qryIDPerCustomer.
Can I use a loop? How do I reference another query?
Another possibility in MS Access (object names borrowed from Tomalak answer):
UPDATE tblStarting_Data, qryIDPerCustomer
SET tblStarting_Data.CustomerID=qryIDPerCustomer.CustomerID
WHERE tblStarting_Data.TEMPCustomer=qryIDPerCustomer.CustomerName
I think a JOIN will help you:
UPDATE
tblStarting_Data AS sd
INNER JOIN qryIDPerCustomer AS qc ON sd.TEMPCustomer = qc.CustomerName
SET
sd.CustomerID = qc.CustomerID;
This can be expressed as a correlated sub-query as well (though the join syntax is preferable):
UPDATE
tblStarting_Data
SET
CustomerID = (
SELECT CustomerID
FROM qryIDPerCustomer
WHERE CustomerName = tblStarting_Data.TEMPCustomer
)
No need for a loop, both statements will update all records in tblStarting_Data in one step.