I have been trying to copy the data listed in one table to another that are both located in the same database. However, every time I have everything entered, it runs the query and says 0 rows updated.
I have tried several variations in an attempt to get this to work. One such attempt is as listed below. I found this while researching in an attempt to get this done.
UPDATE
t1
SET
t1.column = t2.column
FROM
Table1 t1
INNER JOIN Table2 t2
ON t1.id = t2.id;
Any help on this would be greatly appreciated.
UPDATE will only modify records that already exist, if you want to insert rows that exist on another table use INSERT.
You can combine INSERT and SELECT to copy a whole table1 into a table2.
INSERT INTO table2 SELECT * FROM table1;
You can use INSERT IGNORE to copy only records that don't exist yet (based on unique keys).
You can also specify fields to copy in case the tables are different:
INSERT INTO table2 (id, first_name, last_name) SELECT id, name, surname FROM table1;
Related
Let's say var_Environment = QA1,QA2.
I have two tables table 1 and table 2. Table 1 has some column name var_Environment =QA1; where as table 2 does have the same column name but no values
Now my task is, I need to copy all the values from table1 to table2 only if condition meets var_Environment =QA2 How will I perform this operation ? Can I use Union All with some condition? Can someone help?
You can use INSERT INTO SELECT like below.
The WHERE clause may need adjustment, so run the the SELECT query by itself to check if the correct rows are selected.
INSERT INTO table2
SELECT var_Environment
FROM Table1
WHERE var_Environment LIKE '%QA2%'
I'm trying to update medical data from one table to another after switching from one system to another. We have two tables, for simplicity I'll make this a simple example. There are many columns in these tables in reality (not just 5).
Table1:
name, date, var1, var2, var3
Table2:
name, date, var1a, var2a, var3a
I want to transfer data from Table 1 to Table 2 for any rows where there isn't previous data for that date, where var1 = var1a, etc (same columns with different names).
I was trying to do something with a loop, but realized that may not be necessary.
I had gotten this far but keep wasn't sure if this was ok:
UPDATE Table2 VALUES (date, var1a, var2a, var3a)
SELECT date, var1, var2, var3 FROM Table1
Is that correct syntax so far? Or do I need to map the variables to translate var1 into var1a, etc?
How do I add a check to make sure I don't overwrite any data already in Table1? I don't want to add data if there is already data for that date/name combination.
Thanks!
You can INSERT into TABLE2 all values from TABLE1 that do not already exist in Table2:
INSERT INTO Table2 (date, var1a, var2a, var3a)
SELECT date, var1, var2, var3
FROM Table1 t1
WHERE NOT EXISTS (SELECT 1 FROM Table2 t2 WHERE t2.date = t1.date)
Already existing values are specified by comparing the date column. You can add any other predicates in the SELECT subquery of the NOT EXISTS expression to suit your needs.
You could use an update with a join. And you dont need to update the date column since that's what you are using to find the matches in the 2 tables.
Either you generate a dynamic query based on the empty/null valued columns, or you could do something like the below, which puts the same value in the column if it exists in table2 or else puts the corresponding value from table1.
The below approach requires less logic and easier to implement but will produce IO equivalent to updating the entire table.
update tbl2
set val1a=isnull(val1a,val1)
, val2a=isnull(val2a,val2)
, val3a=isnull(val3a.val3)
from table1 tbl1
inner join table2 tbl2
on tbl1.name=tbl2.name
and tbl1.date=tbl2.date
Considerations:
The approach requires less logic and easier to implement but will produce IOs equivalent to updating the entire table2. If you have a smallish table i would go with this approach.
If its a big table then you should look into building specific query sets to reduce IO
This code is tested in Access but something very similar should work in SQL Server 2012:
UPDATE Table2 RIGHT JOIN Table1 ON Table2.date = Table1.date
SET Table2.name = Table1.name, Table2.date = Table1.date, Table2.var1 = Table1.var1a, Table2.var2 = Table1.var2a, Table2.var3 = Table1.var3a
WHERE (Table2.date Is Null);
Explanation: this uses a right join so that within the query all the data from Table1 is present and where there is a matched date for Table2 that data is present too. We then ignore all cases where there is any data for Table2 and update the query in all other cases - the update in fact inserts new data into Table2.
I have two tables in my SQLite Database (dummy names):
Table 1: FileID F_Property1 F_Property2 ...
Table 2: PointID ForeignKey(fileid) P_Property1 P_Property2 ...
The entries in Table2 all have a foreign key column that references an entry in Table1.
I now would like to select entries from Table2 where for example F_Property1 of the referenced file in Table1 has a specific value.
I tried something naive:
select * from Table2 where fileid=(select FileID from Table1 where F_Property1 > 1)
Now this actually works..kind of. It selects a correct file id from Table1 and returns entries from Table2 with this ID. But it only uses the first returned ID. What I need it to do is basically connect the returned IDs from the inner select by OR so it returns data for all the IDs.
How can I do this? I think it is some kind of cross-table-query like what is asked here What is the proper syntax for a cross-table SQL query? but these answers contain no explaination of what they are actually doing so I'm struggeling with any implementation.
They are using JOIN statements, but wouldn't this mix entries from Table1 and Table2 together while only checking matching IDs in both tables? At least that is how I understand this http://www.codeproject.com/Articles/33052/Visual-Representation-of-SQL-Joins
As you may have noticed from the style, I'm very new to using databases in general, so please forgive me if not everything is clear about what I want. Please leave a comment and I will try to improve the question if neccessary.
The = operator compares a single value against another, so it is assumed that the subquery returns only a single row.
To check whether a (column) value is in a set of values, use IN:
SELECT *
FROM Table2
WHERE fileid IN (SELECT FileID
FROM Table1
WHERE F_Property1 > 1)
The way joins work is not by "mixing" the data, but sort of combining them based on the key.
In your case (I am assuming the key field in Table 1 is unique), if you join those two tables on the primary key field, you will end up with all the entries in table2 plus all corresponding fields from table1. If you were doing this:
select * from table1, table2 where table1.fieldID=table2.foreignkey;
then, providing your key fields are set up right, you will end up with the following:
PointID ForeignKey(fileid) P_Property1 P_Property2 FileID F_Property1 F_Property2
The field values from table1 would be from matching rows.
Now, if you do this:
select table1.* from table 1, table2 where
table1.fieldID=table2.foreignkey and F_Property1>1;
Would essentially get the same set of records, but will only show the columns from the second table, and only those that satisfy the where condition for the first one.
Hope this helps :)
If I understood your question correctly this will get the job done.
Select t2.*
from table1 t1
inner join table2 t2 on t2.id = t1.id
where t1.Prop = 'SomeValue'
I am trying to make an MS SQL database, and I am quite new to this.
Lets say I have tables with columns
Table1=[Client_ID, Client_Name]
Table2=[Product, Client_ID]. (Client_ID is a FK to Table1)
Now I want to update data in Table 2 and I already have some info in Table 1. Is there a way to insert into T2 if I only know Product and Client_Name? (Somehow lookup client_ID in first table based on his name) What if I dont have that specific client in Table1 yet, can he be inserted during the insertion in T2?
Also I need to grab the data from T2, but I would want to see a table that is [Product, Client_Name]. Is that kind of lookup/replace possible in SQL?
I know I could try to solve these problems beforehand - I'm using Excel as a frontend for accessing my DB, but I hope there is an easier way to do this with SQL itself.
You can insert into Table 2 as follows
'You are passing #Product, #Client_Name
'First look for whether client name is present in table1
declare #clientId as integer;
select #clientId =Client_ID from Table1 where Client_Name=#Client_Name
if #clientId >0 'When there is client name in Table1
begin
insert into table2
values(#Product, #clientId)
end
else 'There is no client name, so we have to insert client name first then gets its id
begin
insert into table1
values(#Client_Name)
'Get id of newly added client, you can done this many way, but here is the simplest way like previous
select #clientId=Client_ID from Table1 where Client_Name=#Client_Name
'Now insert into table2
insert into table2
values(#Product, #clientId)
end
You can get the data the way you wanted by using Join
Select Table2.Product, Table1.Client_Name from table1 inner join table2 on table1.Client_ID = table2.Client_ID
I am confused about this query where it uses insert statement and then ignore and then select. Can someone explain me this? Thanks
INSERT IGNORE INTO
myTable
SELECT
$var1 AS `CMMNCTID`,
$var2 AS `ENCID`,
variableID,
ProductID,
CustomerID,
Age,
"" AS `myJ`,
"" AS `myI`
FROM
table2
JOIN
table3
ON
table2.ID= table3.ID
INSERT IGNORE in a keyword mysql: If the insert will cause a Primary key or Unique key error, it should skip that row.
INSERT ... SELECT: is used to copy data from another table.
http://dev.mysql.com/doc/refman/5.1/en/insert.html
The SELECT is a subquery. What the INSERT is doing is inserting whatever is contained in the join of table2 and table3, into myTable. The IGNORE tells it to ignore any entries for keys that already exist in myTable and to just insert whatever doesn't yet exist.
It seems the purpose of the query is to combine the data that is associated between table2 and table3 and dump it into myTable.
It takes results from the SELECT query on tables table2 and table3 and inserts the results into table myTable. IGNORE keyword simply tells mysql to ignore any errors that occur while executing the INSERT query.