I currently have a few unpivot queries that yeilds about 2000 rows each. I need to take the results of those queires, and put in a new table to match on a key.
Query Example:
Select DeviceSlot
FROM tbl1
unpivot(
DeviceSlot
For col in(
col1,
col2,
col3,
)
)AS Unpivot
Now I need to match the results from the query, and insert it into a new table with about 20,000 rows.
Pseudo-Code for this:
Insert Into tbl2(DeviceSlot)
Select DeviceSlot
FROM tbl1
unpivot(
DeviceSlot
For col in(
col1,
col2,
col3
)
)AS Unpivot2
Where tbl1.key = tbl2.key
I've been pretty confused on how to do this, and I apologize if it is not clear.
I also have another unpivot query doing the same thing for different columns.
Not sure what you are asking for. While unpivoting to "normalize" data typically the wanted "key" is derived during the unpivot, for example, below the id column of the original table is repeated in the un-pivoted data to represent a foreign key for some new table.
SQL Fiddle
MS SQL Server 2014 Schema Setup:
CREATE TABLE Table1
([id] int, [col1] varchar(2), [col2] varchar(2), [col3] varchar(2))
;
INSERT INTO Table1
([id], [col1], [col2], [col3])
VALUES
(1, 'a', 'b', 'c'),
(2, 'aa', 'bb', 'cc')
;
Query 1:
select id as table1_fk, colheading, colvalue
from (
select * from table1
) t
unpivot (
colvalue for colheading in (col1, col2, col3)
) u
Results:
| table1_fk | colheading | colvalue |
|-----------|------------|----------|
| 1 | col1 | a |
| 1 | col2 | b |
| 1 | col3 | c |
| 2 | col1 | aa |
| 2 | col2 | bb |
| 2 | col3 | cc |
Related
For reasons of our IT department, I am stuck doing this entirely within an SQL query.
Simplified, I have this as an input table:
And I need to create this:
And I am just not sure where to start with this. In my normal C# way of thinking its easy. Column1 is ordered, if the value in Col1 is new, then add a new row to the output and put the contents in column1 in the output. Then, whilst the contents of the input Column1 is unchanged, keep adding the contents of column2 to new rows.
In SQL... nope, I just cannot see the right way to start!
This is a presentation issue that can be easily done in the application or presentation layer. In SQL this can be clunky. The goal of a database is not to render a UI but to store and retrieve data fast and also efficiently, in order to serve as many clients as possible with the same hardware and software resources constraints.
The query that could do this can look like:
with
y as (
select col1, row_number() over(order by col1) as r1
from (select distinct col1 as col1 from t) x
),
z as (
select
t.col1, y.r1, t.col2,
row_number() over(partition by t.col1 order by t.col2) as r2
from t
join y on y.col1 = x.col1
)
select col1, col2
from (
select col1, null as col2, r1, 0 from y
union all
select null, col2, r1, r2 from z
) w
order by r1, r2
As you see, it looks clunky and bloated.
You need a header row for each group which will consist of col1 and null and all the rows of the table with null as col1.
You can do it with UNION ALL and conditional sorting:
select
case when t.col2 is null then t.col1 end col1,
t.col2
from (
select col1, col2 from tablename
union all
select distinct col1, null from tablename
) t
order by
t.col1,
case when t.col2 is null then 1 else 2 end,
t.col2
See the demo (for MySql but it is standard SQL).
Results:
| col1 | col2 |
| ---- | ----- |
| SetA | |
| | BH101 |
| | BH102 |
| | BH103 |
| SetB | |
| | BH201 |
| | BH202 |
| | BH203 |
I agree, formatting should be done outside of SQL, but if you have no choice, here is some SQL Server code that will generate your output
select *
from (
select top 100
case
when col2 is null then ' '+col1
else '' end as firstCol,
IsNull(col2,'') as Col2
from dbo.test t1
group by col1,col2 with rollup
order by col1,col2
) x
where x.firstcol is not null
I need to merge a table with ID and various bit flags like this
-----------------
a1 | x | | x |
-----------------
a1 | | x | |
-----------------
a1 | | | |
-----------------
b2 | x | | |
-----------------
b2 | | | |
-----------------
c3 | x | x | x |
into such form
-----------------
a1 | x | x | x |
-----------------
b2 | x | | |
-----------------
c3 | x | x | x |
The problem is that data are join by kind of option ID each option has an unique ID which is joined with a1, b2. When I try to SELECT it by using DISTINCT I receive results from table number 1. I can make it by subqueries in SELECT but it is really weak solution due to performance reasons.
Do you have any idea how select and combine all these flags into single row?
use aggregation
select col1 ,max(col2),max(col3),max(col4)
form table_name group by col1
For the given result set it is eligible to use MIN and GROUP BY:
SELECT
tbl.Col
, MIN(tbl.Col1) Col1
, MIN(tbl.Col2) Col2
, MIN(tbl.Col3) Col3
FROM #table tbl
GROUP BY tbl.Col
However, if you have empty rows, then use MAX(). Otherwise MIN() returns empty rows:
SELECT
tbl.Col
, MAX(tbl.Col1) Col1
, MAX(tbl.Col2) Col2
, MAX(tbl.Col3) Col3
FROM #table tbl
GROUP BY tbl.Col
For example:
DECLARE #table TABLE
(
Col VARCHAR(50),
Col1 VARCHAR(50),
Col2 VARCHAR(50),
Col3 VARCHAR(50)
)
INSERT INTO #table
(
Col,
Col1,
Col2,
Col3
)
VALUES
( 'a1', -- Col - varchar(50)
'x', -- Col1 - varchar(50)
Null, -- Col2 - varchar(50)
'x' -- Col3 - varchar(50)
)
, ('a1', NULL, 'x', null)
, ('a1', NULL, 'x', null)
, ('b2', 'x', null, null)
, ('b2', null, null, null)
, ('c3', 'x', 'x', 'x')
SELECT
tbl.Col
, MIN(tbl.Col1) Col1
, MIN(tbl.Col2) Col2
, MIN(tbl.Col3) Col3
FROM #table tbl
GROUP BY tbl.Col
OUTPUT:
Col Col1 Col2 Col3
a1 x x x
b2 x NULL NULL
c3 x x x
You want aggregation :
select col1, max(col2), max(col2), max(col3)
from table t
group by col1;
This assuming blank value as null.
The general solution for such a situation is to simply aggregate and either use MIN or MAX on the columns.
SQL Server's data type BIT, however, is quirky. It's a little like a BOOLEAN, but not a real boolean. It is a little like a very limited numeric data type, but it isn't really a numeric type either. And there simply exist no aggregation functions for this data type. In standard SQL you'd have ANY and EVERY for the BOOLEAN type. In PostgreSQL you have BIT_OR and BIT_AND for BIT and BOOL_OR and BOOL_AND for BOOLEAN. SQL Server has nothing.
So convert your columns to a numeric type before using MIN (which would be a bitwise AND) or MAX (which would be a bitwise OR) on it. E.g.
select
id,
max(bit1 + 0) as bit1agg,
max(bit2 + 0) as bit2agg,
max(bit3 + 0) as bit3agg
from mytable
group by id
order by id;
You can also use CAST or CONVERT instead of course.
I have example table like this:
Column1 Column2 Column3 Column4 Column5
---------------------------------------------------------------
Dog 456 Long Short Small
Car 454 Blue NULL NULL
Fruit 466 Apple Pear NULL
And I expect table like this when XY columns will be put into 1 column
Column1 Column2 Column3
------------------------------
Dog 456 Long
Dog 456 Short
Dog 456 Small
Car 454 Blue
Fruit 466 Apple
Fruit 466 Pear
Thank you for your opinions when tables have over thousand rows.
Even I can do this in excel and then back import data to SQL Server
You can use unpivot as below:
Select * from #unpivotdata
unpivot( cols for col in([column3],[column4],[column5])) u
Output as below:
+---------+---------+-------+
| Column1 | column2 | cols |
+---------+---------+-------+
| Dog | 456 | Long |
| Dog | 456 | Short |
| Dog | 456 | Small |
| Car | 454 | Blue |
| Fruit | 466 | Apple |
| Fruit | 466 | Pear |
+---------+---------+-------+
SELECT Column1, Column2, Column3 FROM table WHERE Column3 IS NOT NULL
UNION ALL
SELECT Column1, Column2, Column4 FROM table WHERE Column4 IS NOT NULL
UNION ALL
SELECT Column1, Column2, Column5 FROM table WHERE Column5 IS NOT NULL
Using UNION ALL:
SELECT col1, col2, col3
FROM tab
UNION ALL
SELECT col1, col2, col4
FROM tab
WHERE col4 IS NOT NULL
SELECT col1, col2, col5
FROM tab
WHERE col5 IS NOT NULL;
UnPivot would be more performant, but if the number of columns is unknowm.
You many notice that only the "Key" columns are identified, so the width is dynamic.
Example
Declare #YourTable Table ([Column1] varchar(50),[Column2] varchar(50),[Column3] varchar(50),[Column4] varchar(50),[Column5] varchar(50))
Insert Into #YourTable Values
('Dog',456,'Long','Short','Small')
,('Car',454,'Blue',NULL,NULL)
,('Fruit',466,'Apple','Pear',NULL)
Select A.[Column1]
,A.[Column2]
,[Column3] = C.Value
From #YourTable A
Cross Apply ( values (cast((Select A.* for XML RAW) as xml))) B(XMLData)
Cross Apply (
Select Field = a.value('local-name(.)','varchar(100)')
,Value = a.value('.','varchar(max)')
From B.XMLData.nodes('/row') as C1(n)
Cross Apply C1.n.nodes('./#*') as C2(a)
Where a.value('local-name(.)','varchar(100)') not in ('Column1','Column2')
) C
Returns
I have a table like this:
| Col1 | Col2 |
|:-----------|------------:|
| 1 | a;b; |
| 1 | b;c; |
| 2 | c;d; |
| 2 | d;e; |
I want the result to be some thing like this.
| Col1 | Col2 |
|:-----------|------------:|
| 1 | a;b;c;|
| 2 | c;d;e;|
Is there some way to write a set function which adds unique values in a column into an array and then displays them. I am using the Redshift Database which mostly uses postgresql with the following difference:
Unsupported PostgreSQL Functions
Have a look at Redshift's listagg() function which is similar to MySQL's group_concat. You would need to split the items first and then use listagg() to give you a list of values. Do take note, though, that, as the documentation states:
LISTAGG does not support DISTINCT expressions
(Edit: As of 11th October 2018, DISTINCT is now supported. See the docs.)
So will have to take care of that yourself. Assuming you have the following table set up:
create table _test (col1 int, col2 varchar(10));
insert into _test values (1, 'a;b;'), (1, 'b;c;'), (2, 'c;d;'), (2, 'd;e;');
Fixed number of items in Col2
Perform as many split_part() operations as there are items in Col2:
select
col1
, listagg(col2, ';') within group (order by col2)
from (
select col1, split_part(col2, ';', 1) as col2 from _test
union select col1, split_part(col2, ';', 2) as col2 from _test
)
group by col1
;
Varying number of items in Col2
You would need a helper here. If there are more rows in the table than items in Col2, a workaround with row_number() could work (but is expensive for large tables):
with _helper as (
select
(row_number() over())::int as part_number
from
_test
),
_values as (
select distinct
col1
, split_part(col2, ';', part_number) as col2
from
_test, _helper
where
length(split_part(col2, ';', part_number)) > 0
)
select
col1
, listagg(col2, ';') within group (order by col2) as col2
from
_values
group by
col1
;
Assuming I have a table containing the following information:
FK | Field1 | Field2
=====================
3 | ABC | *NULL*
3 | *NULL* | DEF
is there a way I can perform a select on the table to get the following
FK | Field1 | Field2
=====================
3 | ABC | DEF
Thanks
Edit: Fix field2 name for clarity
Aggregate functions may help you out here. Aggregate functions ignore NULLs (at least that's true on SQL Server, Oracle, and Jet/Access), so you could use a query like this (tested on SQL Server Express 2008 R2):
SELECT
FK,
MAX(Field1) AS Field1,
MAX(Field2) AS Field2
FROM
table1
GROUP BY
FK;
I used MAX, but any aggregate which picks one value from among the GROUP BY rows should work.
Test data:
CREATE TABLE table1 (FK int, Field1 varchar(10), Field2 varchar(10));
INSERT INTO table1 VALUES (3, 'ABC', NULL);
INSERT INTO table1 VALUES (3, NULL, 'DEF');
INSERT INTO table1 VALUES (4, 'GHI', NULL);
INSERT INTO table1 VALUES (4, 'JKL', 'MNO');
INSERT INTO table1 VALUES (4, NULL, 'PQR');
Results:
FK Field1 Field2
-- ------ ------
3 ABC DEF
4 JKL PQR
There are a few ways depending on some data rules that you have not included, but here is one way using what you gave.
SELECT
t1.Field1,
t2.Field2
FROM Table1 t1
LEFT JOIN Table1 t2 ON t1.FK = t2.FK AND t2.Field1 IS NULL
Another way:
SELECT
t1.Field1,
(SELECT Field2 FROM Table2 t2 WHERE t2.FK = t1.FK AND Field1 IS NULL) AS Field2
FROM Table1 t1
There might be neater methods, but the following could be one approach:
SELECT t.fk,
(
SELECT t1.Field1
FROM `table` t1
WHERE t1.fk = t.fk AND t1.Field1 IS NOT NULL
LIMIT 1
) Field1,
(
SELECT t2.Field2
FROM `table` t2
WHERE t2.fk = t.fk AND t2.Field2 IS NOT NULL
LIMIT 1
) Field2
FROM `table` t
WHERE t.fk = 3
GROUP BY t.fk;
Test Case:
CREATE TABLE `table` (fk int, Field1 varchar(10), Field2 varchar(10));
INSERT INTO `table` VALUES (3, 'ABC', NULL);
INSERT INTO `table` VALUES (3, NULL, 'DEF');
INSERT INTO `table` VALUES (4, 'GHI', NULL);
INSERT INTO `table` VALUES (4, NULL, 'JKL');
INSERT INTO `table` VALUES (5, NULL, 'MNO');
Result:
+------+--------+--------+
| fk | Field1 | Field2 |
+------+--------+--------+
| 3 | ABC | DEF |
+------+--------+--------+
1 row in set (0.01 sec)
Running the same query without the WHERE t.fk = 3 clause, it would return the following result-set:
+------+--------+--------+
| fk | Field1 | Field2 |
+------+--------+--------+
| 3 | ABC | DEF |
| 4 | GHI | JKL |
| 5 | NULL | MNO |
+------+--------+--------+
3 rows in set (0.01 sec)
I had a similar problem. The difference was that I needed far more control over what I was returning so I ended up with an simple clear but rather long query. Here is a simplified version of it based on your example.
select main.id, Field1_Q.Field1, Field2_Q.Field2
from
(
select distinct id
from Table1
)as main
left outer join (
select id, max(Field1)
from Table1
where Field1 is not null
group by id
) as Field1_Q on main.id = Field1_Q.id
left outer join (
select id, max(Field2)
from Table1
where Field2 is not null
group by id
) as Field2_Q on main.id = Field2_Q.id
;
The trick here is that the first select 'main' selects the rows to display. Then you have one select per field. What is being joined on should be all of the same values returned by the 'main' query.
Be warned, those other queries need to return only one row per id or you will be ignoring data
if one row has value in field1 column and other rows have null value then this Query might work.
SELECT
FK,
MAX(Field1) as Field1,
MAX(Field2) as Field2
FROM
(
select FK,ISNULL(Field1,'') as Field1,ISNULL(Field2,'') as Field2 from table1
)
tbl
GROUP BY FK
My case is I have a table like this
---------------------------------------------
|company_name|company_ID|CA | WA |
---------------------------------------------
|Costco | 1 |NULL | 2 |
---------------------------------------------
|Costco | 1 |3 |Null |
---------------------------------------------
And I want it to be like below:
---------------------------------------------
|company_name|company_ID|CA | WA |
---------------------------------------------
|Costco | 1 |3 | 2 |
---------------------------------------------
Most code is almost the same:
SELECT
FK,
MAX(CA) AS CA,
MAX(WA) AS WA
FROM
table1
GROUP BY company_name,company_ID
The only difference is the group by, if you put two column names into it, you can group them in pairs.
SELECT Q.FK
,ISNULL(T1.Field1, T2.Field2) AS Field
FROM (SELECT FK FROM Table1
UNION
SELECT FK FROM Table2) AS Q
LEFT JOIN Table1 AS T1 ON T1.FK = Q.FK
LEFT JOIN Table2 AS T2 ON T2.FK = Q.FK
If there is one table, write Table1 instead of Table2