I'm trying to merge/join two tables.
TABLE1 (left) is the main table I am trying to join on, it contains:
strings that are in TABLE2;
strings that are not in TABLE2;
null values (normal in my case and would like them to be kept)
I use the following command:
SELECT *
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.UNIQUE_ID = TABLE2.UNIQUE_ID_OF_CUSTOMERS
The issue is that it drops all the rows that are not in TABLE2 and does a form of a weird join that I cannot understand how to fix
The first one will only return rows where AGE > 40, so a NULL will not be true. The second one moves the filter to the ON clause, so you will get rows where TABLE2 row is null.
SELECT *
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.UNIQUE_ID = TABLE2.UNIQUE_ID_OF_CUSTOMERS
WHERE TABLE2.AGE > 40
SELECT *
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.UNIQUE_ID = TABLE2.UNIQUE_ID_OF_CUSTOMERS
AND TABLE2.AGE > 40
Related
I'm working on the below query.
SELECT *
FROM eg_table1
LEFT JOIN eg_table2 ON eg_table1.part_id = eg_table2.PRODNO
WHERE eg_table1.part_id LIKE "%ARG1%" AND eg_table2.CCI_PROJECT_ID LIKE '%ARG2%'
It works fine, however, when ARG1 is not contained in table2 it doesn't return anything. Could anyone help me find a way to add a functionality to this query to show ARG1 and an indicator that the value is in table 1 but not in table 2?
When selecting records that are contained in Table1 and not in Table2, this query is usually written that:
select * from Table1 t1
left join Table2 t2 on t2.example_id = t1.example_id
where t2.id is null
And be careful: When using left join, so joining conditions should be after the on command, not in the where clause.
If you want to show records that contained ARG1 in Table1 and not contained in Table2, let's change your query:
SELECT *
FROM eg_table1 t1
LEFT JOIN eg_table2 t2 ON
t1.part_id = t2.PRODNO and
t2.CCI_PROJECT_ID LIKE '%ARG1%'
WHERE
t1.part_id LIKE "%ARG1%" and
t2.PRODNO is null
How will this query work? I explain:
Table1 will be filtered by this condition: t1.part_id LIKE "%ARG1%"
Table2 will be joined to Table1 by these conditions: (t1.part_id = t2.PRODNO and t2.CCI_PROJECT_ID LIKE '%ARG1%')
Query will be shown records that t1.part_id LIKE "%ARG1%" = true and (t1.part_id = t2.PRODNO and t2.CCI_PROJECT_ID LIKE '%ARG1%') = false
I have 2 tables that showing data Item master and BOM. I would like to join the tables between Item master as T1 and BOM as T2 and the additional table for table BOM as T3. Item master table containing ITM_CD, ITM_TYP (1,2,3,4) where each ITM_TYP represents a code for the first digit on ITM_CD. The thing that I want is like the picture below
CHILD_CD2 value replace to CHILD_CD1 value. So the data should be like this. What query should I fix ? I am very new using oracle query.
Here is mycode;
SELECT DISTINCT
T1.ITM_CD,
T2.C_ITM_CD AS CHILD_CD1,
T3.C_ITM_CD AS CHILD_CD2
FROM CM_HINMO_ALL T1
INNER JOIN (SELECT P_ITM_CD, C_ITM_CD, BOM_PTN FROM SM_BOM_ALL) T2
ON T1.ITM_CD = T2.P_ITM_CD
LEFT JOIN (SELECT P_ITM_CD, C_ITM_CD, BOM_PTN FROM SM_BOM_ALL) T3
ON T2.C_ITM_CD = t3.P_ITM_CD
WHERE 0=0
AND T2.BOM_PTN IN (1)
AND T1.ITM_TYP IN (1,2)
AND T1.ITM_CD = '110100370'
ORDER BY 2
Just use Case expression to replace the values.
SELECT ITM_CD, CASE WHEN CHILD_CD2 IS NULL THEN CHILD_CD2 ELSE CHILD_CD1 END AS CHILD_CD1
FROM TABLE1
If I understood, you want child_cd2 value should taken precedence over child_cd1 if available. If this assumption is right then we can use coalesce which returns the fist non null expression to achieve the same.
SELECT DISTINCT
T1.ITM_CD,
COALESCE(T3.C_ITM_CD,T2.C_ITM_CD) AS CHILD_CD1
FROM CM_HINMO_ALL T1
INNER JOIN SM_BOM_ALL T2
ON T1.ITM_CD = T2.P_ITM_CD
LEFT JOIN SM_BOM_ALL T3
ON T2.C_ITM_CD = t3.P_ITM_CD
WHERE T2.BOM_PTN IN (1)
AND T1.ITM_TYP IN (1,2)
AND T1.ITM_CD = '110100370'
ORDER BY 2
I want to join two tables in Access based on different wildcards for different rows.
The first, table1, contains rows with different wildcards and table2 contains the column that should be matched with the wildcards in table1.
I imagine the SQL code to look like:
SELECT *
FROM table2
LEFT JOIN table1
ON table2.subject LIKE table1.wildcard
The tables look like this: https://imgur.com/a/O9OPAL6
The third pictures shows the result that I want.
How do I execute the join or is there an alternative?
I don't think MySQL support non-equality conditions for JOINs. So, you can do this as:
SELECT * -- first get the matches
FROM table2 as t2, -- ugg, why doesn't it support CROSS JOIN
table1 as t1
WHERE t2.subject LIKE t1.wildcard
UNION ALL
SELECT * -- then get the non-matches
FROM table2 as t2 LEFT JOIN
table1 as t1
ON 1 = 0 -- always false but gets the same columns
WHERE NOT EXISTS (SELECT 1
FROM table1 as t1
WHERE t2.subject LIKE t1.wildcard
);
For example, there are two tables:
create table Table1 (id int, Name varchar (10))
create table Table2 (id int, Name varchar (10))
Table1 data as follows:
Id Name
-------------
1 A
2 B
Table2 data as follows:
Id Name
-------------
1 A
2 B
3 C
If I execute both below mentioned SQL statements, both outputs will be the same:
select *
from Table1
left join Table2 on Table1.id = Table2.id
select *
from Table2
right join Table1 on Table1.id = Table2.id
Please explain the difference between left and right join in the above SQL statements.
Select * from Table1 left join Table2 ...
and
Select * from Table2 right join Table1 ...
are indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
Table from which you are taking data is 'LEFT'.
Table you are joining is 'RIGHT'.
LEFT JOIN: Take all items from left table AND (only) matching items from right table.
RIGHT JOIN: Take all items from right table AND (only) matching items from left table.
So:
Select * from Table1 left join Table2 on Table1.id = Table2.id
gives:
Id Name
-------------
1 A
2 B
but:
Select * from Table1 right join Table2 on Table1.id = Table2.id
gives:
Id Name
-------------
1 A
2 B
3 C
you were right joining table with less rows on table with more rows
AND
again, left joining table with less rows on table with more rows
Try:
If Table1.Rows.Count > Table2.Rows.Count Then
' Left Join
Else
' Right Join
End If
You seem to be asking, "If I can rewrite a RIGHT OUTER JOIN using LEFT OUTER JOIN syntax then why have a RIGHT OUTER JOIN syntax at all?" I think the answer to this question is, because the designers of the language didn't want to place such a restriction on users (and I think they would have been criticized if they did), which would force users to change the order of tables in the FROM clause in some circumstances when merely changing the join type.
select fields
from tableA --left
left join tableB --right
on tableA.key = tableB.key
The table in the from in this example tableA, is on the left side of relation.
tableA <- tableB
[left]------[right]
So if you want to take all rows from the left table (tableA), even if there are no matches in the right table (tableB), you'll use the "left join".
And if you want to take all rows from the right table (tableB), even if there are no matches in the left table (tableA), you will use the right join.
Thus, the following query is equivalent to that used above.
select fields
from tableB
right join tableA on tableB.key = tableA.key
Your two statements are equivalent.
Most people only use LEFT JOIN since it seems more intuitive, and it's universal syntax - I don't think all RDBMS support RIGHT JOIN.
I feel we may require AND condition in where clause of last figure of Outer Excluding JOIN so that we get the desired result of A Union B Minus A Interaction B.
I feel query needs to be updated to
SELECT <select_list>
FROM Table_A A
FULL OUTER JOIN Table_B B
ON A.Key = B.Key
WHERE A.Key IS NULL AND B.Key IS NULL
If we use OR , then we will get all the results of A Union B
select *
from Table1
left join Table2 on Table1.id = Table2.id
In the first query Left join compares left-sided table table1 to right-sided table table2.
In Which all the properties of table1 will be shown, whereas in table2 only those properties will be shown in which condition get true.
select *
from Table2
right join Table1 on Table1.id = Table2.id
In the first query Right join compares right-sided table table1 to left-sided table table2.
In Which all the properties of table1 will be shown, whereas in table2 only those properties will be shown in which condition get true.
Both queries will give the same result because the order of table declaration in query are different like you are declaring table1 and table2 in left and right respectively in first left join query, and also declaring table1 and table2 in right and left respectively in second right join query.
This is the reason why you are getting the same result in both queries. So if you want different result then execute this two queries respectively,
select *
from Table1
left join Table2 on Table1.id = Table2.id
select *
from Table1
right join Table2 on Table1.id = Table2.id
Select * from Table1 t1 Left Join Table2 t2 on t1.id=t2.id
By definition: Left Join selects all columns mentioned with the "select" keyword from Table 1 and the columns from Table 2 which matches the criteria after the "on" keyword.
Similarly,By definition: Right Join selects all columns mentioned with the "select" keyword from Table 2 and the columns from Table 1 which matches the criteria after the "on" keyword.
Referring to your question, id's in both the tables are compared with all the columns needed to be thrown in the output. So, ids 1 and 2 are common in the both the tables and as a result in the result you will have four columns with id and name columns from first and second tables in order.
*select *
from Table1
left join Table2 on Table1.id = Table2.id
The above expression,it takes all the records (rows) from table 1 and columns, with matching id's from table 1 and table 2, from table 2.
select *
from Table2
right join Table1 on Table1.id = Table2.id**
Similarly from the above expression,it takes all the records (rows) from table 1 and columns, with matching id's from table 1 and table 2, from table 2. (remember, this is a right join so all the columns from table2 and not from table1 will be considered).
Hi I have 2 tables. I want to list
all records in table1 which are present in
table2
all records in table2 which are not present in table1 with a where condition
Null rows will be returned by table1 in second condition but I am unable to get the query working correctly. It is only returning null rows
SELECT
A.CLMSRNO,A.CLMPLANO,A.GENCURRCODE,A.CLMNETLOSSAMT,
A.CLMLOSSAMT,A.CLMCLAIMPRCLLOSSSHARE
FROM
PAKRE.CLMCLMENTRY A
RIGHT OUTER JOIN (
SELECT
B.CLMSRNO,B.UWADVICETYPE,B.UWADVICENO,B.UWADVPREMCURRCODE,
B.GENSUBBUSICLASS,B.UWADVICENET,B.UWADVICEKIND,B.UWADVYEAR,
B.UWADVQTR,B.ISMANUAL,B.UWCLMNOREFNO
FROM
PAKRE.UWADVICE B
WHERE
B.ISMANUAL=1
) r
ON a.CLMSRNO=r.CLMSRNO
ORDER BY
A.CLMSRNO DESC;
Which OS are you using ?
Table aliases are case sensistive on some platforms, which is why your join condition ON a.CLMSRNO=r.CLMSRNO fails.
Try with A.CLMSRNO=r.CLMSRNO and see if that works
I'm not understanding your first attempt, but here's basically what you need, I think:
SELECT *
FROM TABLE1
INNER JOIN TABLE2
ON joincondition
UNION ALL
SELECT *
FROM TABLE2
LEFT JOIN TABLE1
ON joincondition
AND TABLE1.wherecondition
WHERE TABLE1.somejoincolumn IS NULL
I think you may want to remove the subquery and put its columns into the main query e.g.
SELECT A.CLMSRNO, A.CLMPLANO, A.GENCURRCODE, A.CLMNETLOSSAMT,
A.CLMLOSSAMT, A.CLMCLAIMPRCLLOSSSHARE,
B.CLMSRNO, B.UWADVICETYPE, B.UWADVICENO, B.UWADVPREMCURRCODE,
B.GENSUBBUSICLASS, B.UWADVICENET, B.UWADVICEKIND, B.UWADVYEAR,
B.UWADVQTR, B.ISMANUAL, B.UWCLMNOREFNO
FROM PAKRE.CLMCLMENTRY A
RIGHT OUTER JOIN PAKRE.UWADVICE B
ON A.CLMSRNO = B.CLMSRNO
WHERE B.ISMANUAL = 1
ORDER
BY A.CLMSRNO DESC;