I have 2 tables: operations with client processing data and customers with age data. I want create new table, vlookup and add new column Age from customers to operations, but it doesnot work:
CREATE TABLE new_schema.total AS (
SELECT new_schema.operations.Id_check,new_schema.operations.ID_client, new_schema.customers.Age
INNER JOIN Age ON new_schema.operations.ID_client=new_schema.customers.ID_client
);
You have some basic syntax errors. There's no FROM clause to specify the first table, and INNER JOIN must be followed by the table you're joining with, not a column.
And you said you wanted the new table to be named vlookup, but you created total instead.
CREATE TABLE new_schema.vlookup AS (
SELECT o.id_check, o.id_client, c.age
FROM new_schema.operations AS o
INNER JOIN new_schema.customers AS c ON o.id_client = c.id_client
);
Related
I have no problem joining the tables, but when I go to create a new table using the joined tables, I get an error saying that I have duplicate columns.
My code:
SELECT *
FROM field
INNER JOIN race
ON field.raceID = race.raceID;
Updated code:
CREATE TABLE fieldrace AS
SELECT f.*, r.*
FROM field f
INNER JOIN race r
ON f.raceID = r.raceID;
That's true of any select. If there are duplicated column names, you have to reference them somehow. For a .* query this would work:
SELECT f.*, r.*
FROM field f
INNER JOIN race r
ON f.raceID = r.raceID;
Individually you can also add aliases. Maybe you have an id column in both race and field tables.
SELECT f.id as field_id, r.id as race_id, ....
FROM field f
INNER JOIN race r
ON f.raceID = r.raceID;
In the query
CREATE TABLE fieldrace AS
SELECT f.*, r.*
FROM field f
INNER JOIN race r
ON f.raceID = r.raceID;
SELECT part produces two columns with the same name in the output.
Two columns with the same name presence is not allowed in table's structure, and the whole query will fail.
General solution is to list each output column in the SELECT part separately with assigning them unique aliases.
If raceID column which is used for joining is the only column whose name interferes then you may use either USING clause instead of ON clause or NATURAL JOIN instead of INNER JOIN.
CREATE TABLE fieldrace AS
SELECT f.*, r.*
FROM field f
INNER JOIN race r USING (raceID);
-- or
CREATE TABLE fieldrace AS
SELECT f.*, r.*
FROM field f
NATURAL INNER JOIN race r;
In both cases the interfered columns will be collapsed into one column which will be placed to the top of created table structure.
Of course when raceID is not the only column whose name interferes then 1st of these queries will fail due to another column duplication whereas 2nd query will use all interfered columns for joining.
You may specify complete or partial structure of newly create table. In this case the amount and relative posession of the columns in the created table won't be changed (will match SELECT output) but all another properties of the columns (datatype, nullability, etc.) and additional objects (indices, constraints, etc.) listed in the structure will be applied. The columns which are absent in the output (including generated ones) will be added into the structure with default values as the most first ones, before the columns used in USING or during NATURAL JOIN even. DEMO.
you can create "view" or name a subquery using "with"
in both cases, you can access it from anywhere in your main query
I have a database scheme like this:
All I want is to query data from these tables where the one in the middle is a bridgetable.
I want to write a query to get Details from WrapupCodes table for all the WrapupIds that exists in Bridgetable for the same contactId as in CallDetails table.
e.g:
Similarly this is the table I want to get details from
And here is the main table.
Thanks in advance.
It is very basic SQL:
SELECT *
FROM WrapupCodes w
INNER JOIN Contact_Wrapup c ON c.WrapupID = w.WrapupID
INNER JOIN CallDetail d on d.ContactID = c.ContactID
E.g. in Pandas, we can apply a mask and create a new dataframe and assign it a name. Similarly in SQL, once I do a LEFT JOIN of 2 tables, is there a way to refer to the new combined table ?
You can join two table and can get the result in the new combined and also you can give name to that table . Just try this query and if get any doubt just feel free to ask anytime.
MYSQL QUERY
EMP(C1, C2, CD1)
DEPT(D1, D2)
SELECT NEWTABLE.First, NEWTABLE.Third
FROM
(SELECT E.C1 AS First, E.C2 AS Second, D.D2 AS Third FROM EMP E, DEPT D WHERE
E.CD1 = D.D1) NEWTABLE
WHERE NEWTABLE.Second > 20;
We have created a virtual table i.e "NEWTABLE" you can give your name also .
(SELECT E.C1 AS First, E.C2 AS Second, D.D2 AS Third FROM EMP E, DEPT D WHERE
E.CD1 = D.D1)
This is the query for where we have applied join query and also we have selected the three row from two table and renamed it as "FIRST", "SECOND" and "THIRD".
And you will get the doubt in the first line so let me clear we have performed the operation NEWTABLE.Second > 20;on the new table which we obtained after join.
If you still get any doubt regarding the query just ask .
Values Stored in the new table is temporary and you can use it for that query only.
And if you want to store permanent value then you have create to new table then assigned that table with the table we joined and so on .
No that won't work in sql, at least not directly
But you can do a subquery
Like
SELECT aa.*
FROM
(SELECT t1.*,t2.* FROM table1 t1 LEFT JOIN table2 t2 ON t1.id = t2.refid) aa
or A view
CREATE VIEW v AS SELECT t1.*,t2.* FROM table1 t1 LEFT JOIN table2 t2 ON t1.id = t2.refid;
A problem can result, when you have in both tables the same names for columns, that would cause problems, so you must check and in case of equal columnames alias the second column
I have a table, System, with a bunch of fields including System.serial.
I have a list of serial numbers that I want to get the status of.
Simple enough:
Select * from System where System.serial in ('s1','s2', 'sn');
However the list of serial numbers also has serials NOT IN the System table.
Obviously they are not in the results.
I want the missing serials to show in the results also but with no data.
The best way I can think of doing this is to make a temporary table with one column, serial, and then left join System on it.
How can I do this without creating a temporary table?
Something like:
Select listOfSerials.serial, System.*
from (Select ('s1','s2', 'sn') as serial ) as ListOfSerials
left join System on System.serial = ListOfSerials.serial;
Thanks,
Ryan
You're on the right track with your solution of creating a virtual table with which to do LEFT JOIN against your real data.
You can create a derived table as a series of UNIONed SELECT statements that select literal values with no table reference.
SELECT listOfSerials.serial, System.*
FROM (
SELECT 's1' AS serial
UNION SELECT 's2'
UNION SELECT 'sn'
) AS ListOfSerials
LEFT JOIN System ON System.serial = ListOfSerials.serial;
You only need to define a column alias in the first SELECT in the UNION. The rest are required to use that column alias.
Creating a reference table to store the list of serials is probably your best option. That would allow you to write a query like:
SELECT r.serial reference_serial, s.serial system_serial
FROM reference_table r
LEFT JOIN system_table s ON s.serial = r.serial
With the LEFT JOIN, serials declared in the reference table but unavailable in the system table will have second column set to NULL.
A quick and dirty work around is to use UNIONed subqueries to emulate the reference table:
SELECT r.serial reference_serial, s.serial system_serial
FROM (
SELECT 'serial1' AS serial
UNION ALL SELECT 'serial2'
UNION ALL SELECT 'serial2'
...
) r
LEFT JOIN system_table s ON s.serial = r.serial
Im trying to update a field in table c based on the results of a comparison between table a and table b. It goes like this:
table a contains the patient name, status and description of their status.
- This is a complete table meant for comparison.
table b contains the patient name and status.
- This table is added to every so often.
table c is the target table which needs to have a particular field updated based on the results from table a and b.
My logic goes like this, so far:
UPDATE tblc
SET patntStatus to results from comparison of table a & table b.
I know I need a JOIN but am unclear as to whether I need one or two - for example join a and b or join the results of a and b to c?
I think the first one is more correct so what is the proper syntax for the update?
Thanks
**UPDATE
Have added the SQL statement that displays what i want to to add to table c
SELECT STATUS, STATUS_DESCRIPTION
FROM tbla INNER JOIN tblb ON
tbla.STATUS = tblb.STATUS
WHERE tblb.STATUS = tbla.STATUS;
You are close to what you need. I don't know what you want to update in C, but assuming that you want Staus_Desc in tblc to match Status_Description in the comparison of A and B:
Save your SQL in a query (e.g. qry_A_B_Compare)
Create an UPDATE query with the following SQL:
:
UPDATE tblc
INNER JOIN qry_A_B_Compare ON tblc.Status = qry_A_B_Compare.Status
SET tblc.Status_Desc = [Status_Description];