I am trying to compare multiple column such as part, quantity, and type with another table. I tried with compare part id without problem but when I want to compare part id with quantity it will cause error such as return nothing.
Below coding is for compare part id only.
INSERT INTO `table3`
SELECT *
FROM table1
WHERE NOT EXISTS (SELECT *
FROM table2
WHERE table2.part = table1.part)
How can I compare part and quantity together to find unmatched record.
A handy method in MySQL is in with tuples:
INSERT INTO `table3` ( . . . )
SELECT . . .
FROM table1
WHERE (part, quantity) NOT IN (SELECT part, quantity FROM table2);
More importantly, you should explicitly list all the columns when using an insert. This helps prevent unexpected problems when inserting data.
There are 2 solutions -
1)
INSERT INTO `table3`
SELECT *
FROM table1
WHERE NOT EXISTS (SELECT *
FROM table2
WHERE table2.part = table1.part And table2.quantity=table1.quantity)
2)
INSERT INTO table2 (part, quantity, type)
SELECT part, quantity, type
FROM table1
ON DUPLICATE KEY UPDATE quantity= VALUES(quantity), type= VALUES(type)
Not sure if it's the best approach, but I'd be tempted to try a null-left-join on either a set of values or a concatenation - e.g.
select t1.*
from mytable1 as t1
left join mytable2 as t2 on t1.foo = t2.foo and t1.bar = t2.bar
where t1.id is null;
The only thing to note is that t1.id (and t2.id) are assumed to be the primary key - i.e. can never be null. The end result of the above should be all the rows in t1 that cannot be joined to a row in t2.
Related
I have two interconnected tables: one stores some general result (table1), the other one details N rows for each result (table2).
Each record in table2 has a field recording the "auto_id" of the table1 row of reference (field is called "ref_id")
I intentionally deleted some records from the table1, but I left the referenced rows in table2.
How can I find all rows with invalid "ref_id"s in table2 that link to a no more existing "auto_id" in table1?
I was thinking something like
SELECT *
FROM table2
WHERE NOT EXISTS(
SELECT auto_id
FROM 'table1'
WHERE 'table2.res_id' = auto_id
)
but there-s obviously some error.
Thanks for the help!
You are using the wrong quotes. Single-quotes (apostrophes, or ASCII 39) are for literal strings. The easiest solution would be to remove the quotes:
SELECT *
FROM table2
WHERE NOT EXISTS(
SELECT auto_id
FROM table1
WHERE table2.res_id = auto_id
);
If you want to quote identifiers in MySQL, use backticks (ASCII 96).
SELECT *
FROM `table2`
WHERE NOT EXISTS(
SELECT auto_id
FROM `table1`
WHERE `table2`.`res_id` = `auto_id`
);
The cleanest way IMHO is an outer join filtering for missing rows:
SELECT t2.*
FROM table2
LEFT JOIN table1 t1 ON t1.auto_id = t2.res_id
WHERE t1.auto_id IS NULL
This works because missed left joins have all nulls in their columns and where clause conditions are applied after the join is made - the IS NULL condition means the only rows returned are those that don't have a matching row in the other table.
As well as being the most efficient (assuming an index on table1.auto_id), it also makes for a briefer query than a NOT IN (...) query.
MySQL JOIN is the best option for you.
Try this:
SELECT *
FROM table2 T2
JOIN table1 T1
ON T2.`res_id` != T1.`auto_id`
I have 2 tables. I want to find out whether the values present in the first table is there in another table with a different field name.
Here is how it looks,
Table1
BillNo
43529179
43256787
35425676
25467778
24354758
45754748
Table2
BNo
113104808
25426577
268579679
2542135464
252525232
235263663
I have 137 records in table1 that needs to be checked against table2.
Instead of doing it one by one using the following command,
Select * from Table2 where BNo = '43529179';
This gives the result for just the mentioned value. Is there a way to check for all the values in a single query?
Thanks!
You can use a sub-select to compare against:
Select * from Table2 where BNo IN (SELECT BillNo FROM Table1);
That will "evalaute" to something like Select * from Table2 where BNo IN (113104808, 25426577, 268579679, 2542135464, 252525232, ...);
Join the tables, and check how many matching records there are:
select
count(*) as Matches
from
Table1 as t1
inner join Table2 as t2 on t2.BNo = t1.BillNo
You can also use a left join to pick out the records in table 1 that has no matching record in table 2:
select
t1.BillNo
from
Table1 as t1
left join Table2 as t2 on t2.BNo = t1.BillNo
where
t2.BNo is null
This must be very trivial but I can't seem to find the solution.
I work with two tables, both without any primary key.
I want to add all the records of the first table to the second table only if they don't exist.
Basically:
INSERT INTO Table2
SELECT Table1.*
FROM Table
WHERE "the record to be added doesn't already exists in Table2"
You could do something like this. You would need to check each relevant column - I have just put in 2 as an example. With a Not Exists clause you can check if a record already existed across multiple columns. With a NOT IN you would only be able to check if a record already existed against one column.
INSERT INTO Table2
SELECT t1.*
FROM Table1 t1
WHERE NOT EXISTS
(
SELECT 1
FROM table2 t2 WHERE
t2.col1 = t1.col1 AND
t2.col2 = t1.col2
)
you could make usage of the EXISTS function:
INSERT INTO Table2
SELECT Table1.*
FROM Table1
WHERE NOT EXISTS(SELECT * FROM table2 WHERE <your expression to compare the two tables goes here>)
But i would advise you to check the use of unique index for your tables
Just an idea - untested:
INSERT INTO Table2
SELECT *
FROM Table1
WHERE NOT EXISTS(SELECT * FROM Table2 WHERE Table2.Field1 = Table1.Field1 AND Table2.Field2 = Table1.Field2)
You must add every Field of both Tables in the WHERE clause of the NOT EXISTS Query
INSERT INTO X.TableX1
(ColumX1,ColumnX2)
SELECT DISTINCT c.[ColumnY1],c.[ColumnY2]
FROM Y.Table2 c INNER JOIN Database.z.Table3 i ON c.ColumnX1= i.ColumnY1
WHERE NOT EXISTS
(
SELECT *
FROM X.TableX1 WHERE
X.TableX1.ColumnX1=c.ColumnY1
)
This is Joining two tables and filtering the data required and updating only the new values to third table on every run
the case is that I need to select a field distinct from table1 (no duplicates) and use the result as a key to select from another table2. And I need this to be in one query. Is this possible?!
table1: hID, hName, hLocation
table2: hID, hFrom, hTo, hRate, hRoomType, hMeals
I want to correct version of this query:
SELECT
*
FROM
table1
JOIN (
DISTINCT
hID
FROM
table2
WHERE
hRoomType = Double Room
ON table1.hID = table2.hID)
expected result: all hotels that offer Double Room thanks much –
thanks for help!
Your question is quite vague and confusing. Is this what you are looking for:
SELECT hID, name, location
FROM table2
INNER JOIN table1
ON table1.hID = table2.hID
GROUP BY table2.hID;
Here is a skeleton to achieve this:
SELECT
* -- Don't forget to list the requested fields instead of using `*`!
FROM (
-- This is the distinct list from table1
SELECT DISTINCT
id
FROM
table1 T1
) DT1
INNER JOIN table2 T2
ON T1.id = T2.reference_to_t1_id
Another solution if you don't want to retrieve any columns from table1:
SELECT
* -- Don't forget to list the requested fields instead of using `*`!
FROM
table2 T2
WHERE
-- Sais that get all record from table2 where this condition matches
-- at least one record
EXISTS (
SELECT 1 FROM table1 T1 WHERE T1.id = T2.reference_to_t1_id
)
For your tables and question
SELECT
hID, hName, hLocation
FROM
table1 T1
WHERE
EXISTS (
SELECT 1 FROM
table2 T2
WHERE
T1.hID = T2.hID
AND T.hRoomType = 'Double' -- Assuming that this is the definition of double rooms
)
Im trying to copy row from table to another using 2 coluom only as the tow table schema is not identical ,
am getting this error
Operand should contain 1 column(s)
Any tips whats wrong with my statement ?
Insert table1 ( screenname,list_id )
Select screenname,list_id
From table2 As T1
Where Not Exists (
Select 1
From table1 As T2
Where
(T2.screenname = T1.screenname,T2.list_id = T1.list_id)
)
try to change where condition from (T2.screenname = T1.screenname,T2.list_id = T1.list_id) to (T2.screenname = T1.screenname AND T2.list_id = T1.list_id)
(note AND keyword instead of comma)
Did you try INSERT INTO...ON DUPLICATE KEY syntax?
See MySQL manual here
You can create a unique index in table1 on the columns screenname and list_id
Then use the following statement
Insert ignore into table1 ( screenname,list_id )
Select screenname,list_id
From table2 As T1
Also try this query -
INSERT INTO table1 (screenname, list_id)
SELECT screenname, list_id FROM table2 t2
LEFT JOIN table1 t1
ON t1.screenname = t2.screenname AND t1.list_id = t2.list_id
WHERE
t1.screenname IS NULL AND t1.list_id IS NULL;
Use simple INSERT IGNORE
INSERT table1 (screenname, list_id) SELECT screenname, list_id FROM table2