SQL Server 2008 R2
I have a table - T1 with id, Title, Firstname, postalcode
Second table - T2 with id, Title and PostalCode.
id is the primarykey in T1 and id is corresponding foreign key in T2.
Now i want to list out the Title from T1, Title from T2 and their id's for the matching id between T1 and T2.
BUT THE MAIN thing is only distinct column values of Title and their correspoding tables T1 and T2 along with their id should be displayed.
For example, If a value 'Mr' is found and if second time if it is found, the value shouldnt be listed again.
Hope iam clear. Please advise.
COALESCE() function could be your friend here.
The Example is a little convoluted, but i think i understand the question.
you will like want to use the Distinct key word:
SELECT DISTINCT T1.Title
FROM T1 INNER JOIN T2 ON T1.id = T2.id
UNION ALL
SELECT DISTINCT T2.Title
FROM T1 INNER JOIN T2 ON T1.id = T2.id
This should grab distinct titles from T1 and T2. I hope this is what you were looking for, if not please describe what you are looking for as far as results a little bit more clearly, if you could add a table view that would be ideal.
Thanks,
~Madullah
Related
I have a query that I'm trying to rework that has over 1,000 columns when I select * FROM several tables. I want to know if there is a way in SQL to tag the column alias with the table alias so i can know from which table the columns are from. It looks like the following:
SELECT *
FROM table1 t1
join table2 t2
join table3 t3
join table4 t4
Current column output:
id, id, id, id, name, name, name, name, order, order, order, order
Desired Column output:
t1.id, t1.name, t1.order, t2.id, t2.name, t2.order,t3.id, t3.name, t3.order, t4.id, t4.name, t4.order
this is a very simple example but you can imagine trying to fish out the column you need of a sea of 1,000 columns trying to figure out what table it came from! Any ideas??
I'm not aware of a way to prefix each column with the column alias. However I do know how you could easily break the columns into groups that would allow you to figure out which table each column comes from.
SELECT 'T1' as [Table1]
, t1.*
, 'T2' as [Table2]
, t2.*
, 'T3' as [Table3]
, t3.*
, t4.* as [Table4]
, t4.*
, 'T5' as [Table5]
, t5.*
FROM table1 t1
join table2 t2
join table3 t3
join table4 t4
This would break out the columns into groups by table and it would break a little bookmark before and after each group to help you understand where they're coming.
I know not exactly what you asked for but I believe it would help you a lot in figuring out what's from what tables.
Your other option is as others have said and specifiying the prefix on every column which it sounds like you don't want to do. However it can be a lot quicker to do this if you drag the columns from the Object Explorer - and use ALT-SHIFT to add the prefix to each column.
Here's an article about copying columns from object explorer - https://www.qumio.com/Blog/Lists/Posts/Post.aspx?ID=56
Her's an article about adjusting code using ALT+SHIFT - https://blogs.msdn.microsoft.com/sql_pfe_blog/2017/04/11/quick-tip-shiftalt-for-multiple-line-edits/
The first method would take less than a method, the 2nd method I could see taking less than 10 minutes even for 1,000 columns.
You have to assign non-default column aliases manually:
select t1.id as t1_id, t1.name as t1_name, t1.order as t1_order,
t2.id as t2_id, t2.name as t2_name, t2.order as t2_order,
. . .
You might find that a spreadsheet or query can help, if you have a lot of columns.
Some products may have exceptions, but generally no, you can't do that. You either have to use wildcards (SELECT *) or specify the columns you wish returned by full and complete name.
If you specify columns, you can "alias" them, set the column name to something other than the source name. For example (psuedo-code, leaving out the "ON" clause):
SELECT
T1.Id as T1_Id
,T2.Id as T2_Id
from table1 T1
join table2 T2
Note that you can combine table aliases with wildcards. For example:
SELECT
T2.*
from table1 T1
join table2 T2
join table3 T3
join table4 T5
will return all the columns from table2, and only from table2. This might help in revising your query by getting a list of the available columns in each table.
I have a table named table1 (table1_id,table1_exp) where table1_exp is foreign key linked with table2 (table2_exp,table2_num)
I want to sum all the table2_num of a same table1_id and then display it as one row.
As far as I understood, these are your tables:
t1 (table1_id ,
table_1_exp)
t2 (table2_exp references table_1_exp,
table2_num)
If that's so,
select t1.table1_id,
sum(t2.table2_num) sum_num
from t2 join t1 on t2.table2_exp = t1.table1_exp
group by t1.table1_id
might be what you want.
Though, I don't understand what "display as one row" means. Each TABLE1_ID's sum would be in one row ... Sample data & expected output would help us help you.
Use group by :
SELECT TABLE1_ID, SUM(T1.table1_exp) FROM TABLE1 T1 GROUP BY T1.TABLE1_ID
table1 (id, name)
table2 (id, name)
Query:
SELECT name
FROM table2
-- that are not in table1 already
SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 with the same value for the name column. If there is no such row, we just leave the table2 portion of our result empty for that row. Then we constrain our selection by picking only those rows in the result where the matching row does not exist. Finally, We ignore all fields from our result except for the name column (the one we are sure that exists, from table1).
While it may not be the most performant method possible in all cases, it should work in basically every database engine ever that attempts to implement ANSI 92 SQL
You can either do
SELECT name
FROM table2
WHERE name NOT IN
(SELECT name
FROM table1)
or
SELECT name
FROM table2
WHERE NOT EXISTS
(SELECT *
FROM table1
WHERE table1.name = table2.name)
See this question for 3 techniques to accomplish this
I don't have enough rep points to vote up froadie's answer. But I have to disagree with the comments on Kris's answer. The following answer:
SELECT name
FROM table2
WHERE name NOT IN
(SELECT name
FROM table1)
Is FAR more efficient in practice. I don't know why, but I'm running it against 800k+ records and the difference is tremendous with the advantage given to the 2nd answer posted above. Just my $0.02.
SELECT <column_list>
FROM TABLEA a
LEFTJOIN TABLEB b
ON a.Key = b.Key
WHERE b.Key IS NULL;
https://www.cloudways.com/blog/how-to-join-two-tables-mysql/
This is pure set theory which you can achieve with the minus operation.
select id, name from table1
minus
select id, name from table2
Here's what worked best for me.
SELECT *
FROM #T1
EXCEPT
SELECT a.*
FROM #T1 a
JOIN #T2 b ON a.ID = b.ID
This was more than twice as fast as any other method I tried.
Watch out for pitfalls. If the field Name in Table1 contain Nulls you are in for surprises.
Better is:
SELECT name
FROM table2
WHERE name NOT IN
(SELECT ISNULL(name ,'')
FROM table1)
You can use EXCEPT in mssql or MINUS in oracle, they are identical according to :
http://blog.sqlauthority.com/2008/08/07/sql-server-except-clause-in-sql-server-is-similar-to-minus-clause-in-oracle/
That work sharp for me
SELECT *
FROM [dbo].[table1] t1
LEFT JOIN [dbo].[table2] t2 ON t1.[t1_ID] = t2.[t2_ID]
WHERE t2.[t2_ID] IS NULL
You can use following query structure :
SELECT t1.name FROM table1 t1 JOIN table2 t2 ON t2.fk_id != t1.id;
table1 :
id
name
1
Amit
2
Sagar
table2 :
id
fk_id
email
1
1
amit#ma.com
Output:
name
Sagar
All the above queries are incredibly slow on big tables. A change of strategy is needed. Here there is the code I used for a DB of mine, you can transliterate changing the fields and table names.
This is the strategy: you create two implicit temporary tables and make a union of them.
The first temporary table comes from a selection of all the rows of the first original table the fields of which you wanna control that are NOT present in the second original table.
The second implicit temporary table contains all the rows of the two original tables that have a match on identical values of the column/field you wanna control.
The result of the union is a table that has more than one row with the same control field value in case there is a match for that value on the two original tables (one coming from the first select, the second coming from the second select) and just one row with the control column value in case of the value of the first original table not matching any value of the second original table.
You group and count. When the count is 1 there is not match and, finally, you select just the rows with the count equal to 1.
Seems not elegant, but it is orders of magnitude faster than all the above solutions.
IMPORTANT NOTE: enable the INDEX on the columns to be checked.
SELECT name, source, id
FROM
(
SELECT name, "active_ingredients" as source, active_ingredients.id as id
FROM active_ingredients
UNION ALL
SELECT active_ingredients.name as name, "UNII_database" as source, temp_active_ingredients_aliases.id as id
FROM active_ingredients
INNER JOIN temp_active_ingredients_aliases ON temp_active_ingredients_aliases.alias_name = active_ingredients.name
) tbl
GROUP BY name
HAVING count(*) = 1
ORDER BY name
See query:
SELECT * FROM Table1 WHERE
id NOT IN (SELECT
e.id
FROM
Table1 e
INNER JOIN
Table2 s ON e.id = s.id);
Conceptually would be: Fetching the matching records in subquery and then in main query fetching the records which are not in subquery.
First define alias of table like t1 and t2.
After that get record of second table.
After that match that record using where condition:
SELECT name FROM table2 as t2
WHERE NOT EXISTS (SELECT * FROM table1 as t1 WHERE t1.name = t2.name)
I'm going to repost (since I'm not cool enough yet to comment) in the correct answer....in case anyone else thought it needed better explaining.
SELECT temp_table_1.name
FROM original_table_1 temp_table_1
LEFT JOIN original_table_2 temp_table_2 ON temp_table_2.name = temp_table_1.name
WHERE temp_table_2.name IS NULL
And I've seen syntax in FROM needing commas between table names in mySQL but in sqlLite it seemed to prefer the space.
The bottom line is when you use bad variable names it leaves questions. My variables should make more sense. And someone should explain why we need a comma or no comma.
I tried all solutions above but they did not work in my case. The following query worked for me.
SELECT NAME
FROM table_1
WHERE NAME NOT IN
(SELECT a.NAME
FROM table_1 AS a
LEFT JOIN table_2 AS b
ON a.NAME = b.NAME
WHERE any further condition);
I am trying to write an SQL query that will return Table1, which has 10 columns. This table consists of a primary key id, 4 foreign key Id columns, and 5 other columns that I want to return but not change. The goal is to do a join to replace the foreign key Ids with their descriptions that are held in other tables.
Here is one attempt with the first FK Id:
Select * from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
This left join returns the description from table2, but does not replace it.
Here is another with the first FK Id:
Select t2.BranchName from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
This returns the name I want, but does not return table1 fully.
For the sake of an example you could pretend that OtherName3, OtherName4, OtherName5 are in tables Table3, Table4, Table5, respectively.
This may seem trivial for experienced SQL devs, but I am having a hard time figuring out the syntax.
Thanks!
I'm not sure what you mean by replace it.
I think you just need to list out all the columns you want:
Select t1.col1, t1.col2, t1.col3, . . .,
t2.name
from Table1 t1 left join
Table2 t2
on t1.BranchId = t2.BranchId;
I don't know what you mean by 'replace' but you just need to qualify what columns from which table you want. That goes for all tables you are joined to, especially if they have the same column name in multiple tables. I put junk columns in since I don't know your tables but you should get the general idea.
Select t2.BranchName, t1.BranchId, t1.Name, t1.Amount, t2.BranchLocation from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
I think this is what you are looking for:
select t1.*, t2.BranchName from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
Return Table1 fully (all columns) and only the description (BranchName) from Table2.
If using SQL Server, see all syntax options for the SELECT clause here:
https://msdn.microsoft.com/en-us/library/ms176104.aspx
Im hoping this is a straight forward question but I cannot work out the syntax for it.
I just need to find if a value within "ID" also exists in "ID2", lets say the tables called "teacher"
ID-ID2
10-1
11-2
12-13
13-4
the only match there is row 4 as 13 also exists in id2, so I would need to pull that out with a select query, can anybody advise? thanks.
Hi on top of this I have a second table called staff with the following setup
ID-Name
1-smith
2-jones
3-bruce
whereby ID is the same ID as in the teacher table, I think I need to join them here but im not sure what to do with the ID in the second table. The only information I need from the second table is the name so the Cartesian product should look like the above only with the processing done from table 1. thanks in advance
scrap that, solved it, thanks
Is this what you want?
select t.*
from teacher t
where exists (select 1 from teacher t2 where t2.id = t.id2);
select *
from teacher
where id in (select distinct id2 from teacher)
or
select t1.*
from teacher t1
join teacher t2 on t1.id = t2.id2
select t1.*
from teacher as t1 ,teacher as t2
where t1.ID = t2.ID2 and t1.ID > t2.ID2