it is possible do a SELECT CASE, decode, nvl or another query function when I need verify if the return of a select query is empty or has a value?
For example, I have this:
Record | type | id_customer
-------+--------+-------------
1 | T | cus1
2 | A | cus2
3 | T | cus3
4 | | cus4
If I do this:
select decode(type,'T','Main','A','Adicional','none') from table where record=1;
I get Main.
If I fo this:
select decode(type,'T','Main','A','Adicional','none') from table where record=4;
I get none.
But if I do this:
select decode(type,'T','Main','A','Aditional','none') from table where record=5;
I get nothing, and is logic. So, I need get the decode value when the row exist and a text if the rows no exist.
So, I tried with SELECT CASE but is not posible get a value using COUNT. For example like this:
SELECT
CASE
WHEN count(1)>0 THEN decode(type,'T','Main','A','Aditional','none')
ELSE '-'
END
FROM TABLE WHERE record=5;
And get a ' - ', or the same if the record is 2, get 'Aditional'
Thanks a lot.
You can use aggregate functions min or max outside expression:
select max(decode(type,'T','Main','A','Aditional','none'))
from table
where record=5;
If query returns one row, you get value of that row. If query returns 0 rows, you get NULL.
Then you can replace NULL using nvl:
select nvl(max(decode(type,'T','Main','A','Aditional','none')), ' - ')
from table
where record=5;
EDIT
Also, if you need to choose one string from several:
select decode(max(decode(type,'T', 2, 'A', 1, 0)), 0, 'none', 1, 'Additional', 2, 'Main', null, ' - ')
from table
where record=5;
This is an option:
select decode(type,'T','Main','A','Aditional','none')
from table
where record = 5
union all
select '-'
from dual
where not exists (select 1 from table where record = 5);
It selects records with record = 5 and unifies them with '-', if no records exits with record = 5. Check out this Fiddle.
Related
Let's suppose I have data like
column
ABC
ABC PQR
ABC (B21)
XYZ ABC
and I wanted output as first string i.e.
ABC
XYZ
i.e. group by column
but I could not able to remove string after space.
I believe that the following would do what you want :-
SELECT * FROM mytable GROUP BY CASE WHEN instr(mycolumn,' ') > 0 THEN substr(mycolumn,1,instr(mycolumn,' ')-1) ELSE mycolumn END;
obviously table and column name changed appropriately.
As an example, using your data plus other data to demonstrate, the following :-
DROP TABLE IF EXISTS mytable;
CREATE TABLE IF NOT EXISTS mytable (mycolumn);
INSERT INTO mytable VALUES ('ABC'),('ABC PQR'),('ABC (B21)'),('XYZ'),('A B'),('AAAAAAAAAAAAAAAAAAAAAAAA B'),(' ABC'),(' XZY');
SELECT * FROM mytable;
SELECT *,group_concat(mycolumn) FROM mytable GROUP BY CASE WHEN instr(mycolumn,' ') > 0 THEN substr(mycolumn,1,instr(mycolumn,' ')-1) ELSE mycolumn END;
DROP TABLE IF EXISTS mytable;
group_concat added to show the columns included in each group
Produces:-
The ungrouped table (first SELECT):-
The grouped result (plus group_concat column) :-
the first row being grouped due to the first character being a space in ABC and XZY
You don't want to do any aggregation, so there is no need for a GROUP BY clause.
Use string functions like SUBSTR() and INSTR() to get the 1st word of each string and then use DISTINCT to remove duplicates from the results:
SELECT DISTINCT SUBSTR(columnname, 1, INSTR(columnname || ' ', ' ') - 1) new_column
FROM tablename
See the demo.
Results:
new_column
ABC
XYZ
I would like to repeat this command as many times as there is still sometextin the field note (several rows from the table itemNotes could have one or more sometext in the field note):
UPDATE itemNotes
SET
note = SUBSTR(note, 0, INSTR(LOWER(note), 'sometext')) || 'abc' || SUBSTR(note, INSTR(LOWER(note), 'sometext')+sometext_len)
WHERE
INSTR(LOWER(note), 'sometext') >= 0;
So a proto-code would be :
While (SELECT * FROM itemNotes WHERE note like "%sometext%") >1
UPDATE itemNotes
SET
note = SUBSTR(note, 0, INSTR(LOWER(note), 'sometext')) || 'abc' || SUBSTR(note, INSTR(LOWER(note), 'sometext')+sometext_len)
WHERE
INSTR(LOWER(note), 'sometext') >= 0;
END
But apparently Sqlite3 doesn't support While loop or for loop. They can be emulated with something like this but I have difficulties integrating what I want with this query:
WITH b(x,y) AS
(
SELECT 1,2
UNION ALL
SELECT x+ 1, y + 1
FROM b
WHERE x < 20
) SELECT * FROM b;
Any idea how to do this?
PS: I don't use replace because I want to replace all the case combinations of sometext (e.g. sometext, SOMEtext, SOmeText...) cf this question
Current input and desired output:
For a single row, a note field could look like (and many rows in the table itemNotescould look like this one):
There is SOmetext and also somETExt and more SOMETEXT and even more sometext
The query should output:
There is abc and also abc and more abc and even more abc
I am doing it on the zotero.sqlite, which is created by this file (line 85). The table is created by this query
CREATE TABLE itemNotes (
itemID INTEGER PRIMARY KEY,
parentItemID INT,
note TEXT,
title TEXT,
FOREIGN KEY (itemID) REFERENCES items(itemID) ON DELETE CASCADE,
FOREIGN KEY (parentItemID) REFERENCES items(itemID) ON DELETE CASCADE
);
You just have your answer in your query:
UPDATE itemNotes
SET
note = SUBSTR(note, 0, INSTR(LOWER(note), 'sometext')) || 'abc' || SUBSTR(note, INSTR(LOWER(note), 'sometext')+sometext_len)
WHERE
note LIKE "%sometext%";
It will update all rows that contain sometext in the note field
UPDATE
If you want to update the field which has multiple occurrences in different cases and maintain the rest of the text the simplest solution imo is to use regex and for that you need an extension
UPDATE itemNotes
SET
note = regex_replace('\bsometext\b',note,'abc')
WHERE
note LIKE "%sometext%";
As recommended by Stephan in his last comment, I used python to do this.
Here is my code :
import sqlite3
import re
keyword = "sometext"
replacement = "abc"
db = sqlite3.connect(path_to_sqlite)
cursor = db.cursor()
cursor.execute(f'SELECT * FROM itemNotes WHERE note like "%{keyword}%"')
for row in cursor.fetchall():
row_regex = re.compile(re.escape(keyword), re.IGNORECASE)
row_regex_replaced = row_regex.sub(replacement, row[2])
rowID = row[0]
sql = "REPLACE INTO itemNotes (itemID,note) VALUES (?,?)"
data = (rowID, row_regex_replaced)
cursor.execute(sql, data)
db.commit()
I am new in oracle and I want to get the value from a column which is stored as "Ashu||123 ||Main Menu|ENG||1|1".
as you can see each value is separated by || symbol.in the above value Ashu is the customer name and 123 is the id, I want both value as customer-name and customer id.
In the query below, I include some test data "on the fly" (not part of the solution; use your actual table name instead of test_data in the main query, and your actual column name instead of str). I included several special cases for testing, to make sure the query works correctly in all cases. I assume the first value (before the first ||) is the customer name and the second the customer id, and the rest of the input string can be ignored. I looked in particular to see that the query handles null values correctly (assuming they may happen in your data).
I left the customer id as a string; if it must be a number, it may be better to wrap it all within to_number().
with
test_data ( str ) as (
select 'Ashu||123||Main Menu|ENG||1|1' from dual union all
select 'Misha||125' from dual union all
select 'Babu||||Main Menu|NZL||?' from dual union all
select 'Rim||' from dual union all
select 'Todd' from dual union all
select '||139||Other Stuff' from dual
)
-- end of test data (only for testing and illustration) - not part of solution
-- SQL query begins BELOW THIS LINE
select str,
regexp_substr(str, '([^|]*)(\|\||$)', 1, 1, null, 1) as cust_name,
regexp_substr(str, '([^|]*)(\|\||$)', 1, 2, null, 1) as cust_id
from test_data
;
STR CUST_NAME CUST_ID
----------------------------- --------- -------
Ashu||123||Main Menu|ENG||1|1 Ashu 123
Misha||125 Misha 125
Babu||||Main Menu|NZL||? Babu
Rim|| Rim
Todd Todd
||139||Other Stuff 139
6 rows selected.
I have an application which has data spread accross 2 tables.
There is a main table Main which has columns - Id , Name, Type.
Now there is a Sub Main table that has columns - MainId(FK), StartDate,Enddate,city
and this is a 1 to many relation (each main can have multiple entries in submain).
Now I want to display columns Main.Id, City( as comma seperated from various rows for that main item from submain), min of start date(from submain for that main item) and max of enddate( from sub main).
I thought of having a function but that will slow things up since there will be 100k records. Is there some other way of doing this. btw the application is in asp.net. Can we have a sql query or some linq kind of thing ?
This is off the top of my head, but firstly I would suggest you create a user defined function in sql to create the city comma separated list string that accepts #mainid, then does the following:
DECLARE #listStr VARCHAR(MAX)
SELECT #listStr = COALESCE(#listStr+',' , '') + city
FROM submain
WHERE mainid = #mainid
... and then return #listStr which will now be a comma separated list of cities. Let's say you call your function MainIDCityStringGet()
Then for your final result you can simply execute the following
select cts.mainid,
cts.cities,
sts.minstartdate,
sts.maxenddate
from ( select distinct mainid,
dbo.MainIDCityStringGet(mainid) as 'cities'
from submain) as cts
join
( select mainid,
min(startdate) as 'minstartdate',
max(enddate) as 'maxenddate'
from submain
group by mainid ) as sts on sts.mainid = cts.mainid
where startdate <is what you want it to be>
and enddate <is what you want it to be>
Depending on how exactly you would like to filter by startdate and enddate you may need to put the where filter within each subquery and in the second subquery in the join you may then need to use the HAVING grouped filter. You did not clearly state the nature of your filter.
I hope that helps.
This will of course be in stored procedure. May need some debugging.
An alternative to creating a stored procedure is performing the complex operations on the client side. (untested):
var result = (from main in context.Main
join sub in context.SubMain on main.Id equals sub.MainId into subs
let StartDate = subs.Min(s => s.StartDate)
let EndDate = subs.Max(s => s.EndDate)
let Cities = subs.Select(s => s.City).Distinct()
select new { main.Id, main.Name, main.Type, StartDate, EndDate, Cities })
.ToList()
.Select(x => new
{
x.Id,
x.Name,
x.Type,
x.StartDate,
x.EndDate,
Cities = string.Join(", ", x.Cities.ToArray())
})
.ToList();
I am unsure how well this is supported in other implimentations of SQL, but if you have SQL Server this works a charm for this type of scenario.
As a disclaimer I would like to add that I am not the originator of this technique. But I immediately thought of this question when I came across it.
Example:
For a table
Item ID Item Value Item Text
----------- ----------------- ---------------
1 2 A
1 2 B
1 6 C
2 2 D
2 4 A
3 7 B
3 1 D
If you want the following output, with the strings concatenated and the value summed.
Item ID Item Value Item Text
----------- ----------------- ---------------
1 10 A, B, C
2 6 D, A
3 8 B, D
The following avoids a multi-statement looping solution:
if object_id('Items') is not null
drop table Items
go
create table Items
( ItemId int identity(1,1),
ItemNo int not null,
ItemValue int not null,
ItemDesc nvarchar(500) )
insert Items
( ItemNo,
ItemValue,
ItemDesc )
values ( 1, 2, 'A'),
( 1, 2, 'B'),
( 1, 6, 'C'),
( 2, 2, 'D'),
( 2, 4, 'A'),
( 3, 7, 'B'),
( 3, 1, 'D')
select it1.ItemNo,
sum(it1.ItemValue) as ItemValues,
stuff((select ', ' + it2.ItemDesc --// Stuff is just used to remove the first 2 characters, instead of a substring.
from Items it2 with (nolock)
where it1.ItemNo = it2.ItemNo
for xml path(''), type).value('.','varchar(max)'), 1, 2, '') as ItemDescs --// Does the actual concatenation..
from Items it1 with (nolock)
group by it1.ItemNo
So you see all you need is a sub query in your select that retrieves a set of all the values you need to concatenate and then use the FOR XML PATH command in that sub query in a clever way. It does not matter where the values you need to concatenate comes from you just need to retrieve them using the sub query.
I have an column in table where this column name is items it contains value like this
itemID items
1 school,college
2 place, country
3 college,cricket
4 School,us,college
5 cricket,country,place
6 football,tennis,place
7 names,tennis,cricket
8 sports,tennis
Now I need to write a search query
Ex: if the user types 'cricket' into a textbox and clicks the button I need to check in the column items for cricket.
In the table I have 3 rows with cricket in the items column (ItemId = 3, 5, 7)
If the user types in tennis,cricket then I need to get the records that match either one. So I need to get 5 row (ItemId = 3, 5, 6, 7, 8)
How do I write a query for this requirement?
You need to start by redesigning your database as this is is a very bad structure. You NEVER store a comma delimited list in a field. First think about waht fields you need and then design a proper database.
The very bad structure of this table (holding multiple values in one column) is the reason you are facing this issue. Your best option is to normalize the table.
But if you can't, then you can use the "Like" operator, with a wildcard
Select * From Table
Where items Like '%cricket%'
or
Select * From Table
Where items Like '%cricket%'
or items Like '%tenis%'
You will need to dynamically construct these sql queries from the inputs the user makes. The other alternative is to write code on the server to turn the comma delimited list of parameters into a table variable or temp table and then join to it..
Delimited values in columns is almost always a bad table design. Fix your table structure.
If for some reason you are unable to do that, the best you can hope for is this:
SELECT * FROM [MyTable] WHERE items LIKE '%CRICKET%'
This is still very bad, for two important reasons:
Correctness. It would return values that only contain the word cricket. Using your tennis example, what if you also had a "tennis shoes" item?
Performance. It's not sargable, which means the query won't work with any indexes you may have on that column. That means your query will probably be incredibly slow.
If you need help fixing this structure, the solution is to add another table — we'll call it TableItems — with a column for your ItemID that will be a foreign key to your original table and an item field (singular) for each of your item values. Then you can join to that table and match a column value exactly. If these items work more like categories, where you want to rows with the "Cricket" item to match the same cricket item, you also want a third table to be an intersection between your original table and the other one I just had you create.
For a single item:
SELECT itemID, items FROM MyTable WHERE items LIKE '%cricket%'
For multiple items:
SELECT itemID, items FROM MyTable WHERE items LIKE '%tennis%' or items LIKE '%cricket%'
You'll need to parse the input and split them up and add each item to the query:
items LIKE '%item1%' or items LIKE '%item2%' or items LIKE '%item3%' ...
I think that in the interest of validity of data, it should be normalized so that you split the Items into a separate table with an item on each row.
In either case, here is a working sample that uses a user defined function to split the incoming string into a Table Variable and then uses JOIN with a LIKE
CREATE FUNCTION dbo.udf_ItemParse
(
#Input VARCHAR(8000),
#Delimeter char(1)='|'
)
RETURNS #ItemList TABLE
(
Item VARCHAR(50) ,
Pos int
)
AS
BEGIN
DECLARE #Item varchar(50)
DECLARE #StartPos int, #Length int
DECLARE #Pos int
SET #Pos = 0
WHILE LEN(#Input) > 0
BEGIN
SET #StartPos = CHARINDEX(#Delimeter, #Input)
IF #StartPos < 0 SET #StartPos = 0
SET #Length = LEN(#Input) - #StartPos - 1
IF #Length < 0 SET #Length = 0
IF #StartPos > 0
BEGIN
SET #Pos = #Pos + 1
SET #Item = SUBSTRING(#Input, 1, #StartPos - 1)
SET #Input = SUBSTRING(#Input, #StartPos + 1, LEN(#Input) - #StartPos)
END
ELSE
BEGIN
SET #Pos = #Pos+1
SET #Item = #Input
SET #Input = ''
END
INSERT #ItemList (Item, Pos) VALUES(#Item, #Pos)
END
RETURN
END
GO
DECLARE #Itemstable TABLE
(
ItemId INT,
Items VarChar (1000)
)
INSERT INTO #Itemstable
SELECT 1 itemID, 'school,college' items UNION
SELECT 2, 'place, country' UNION
SELECT 3, 'college,cricket' UNION
SELECT 4, 'School,us,college' UNION
SELECT 5, 'cricket,country,place' UNION
SELECT 6, 'footbal,tenis,place' UNION
SELECT 7, 'names,tenis,cricket' UNION
SELECT 8, 'sports,tenis'
DECLARE #SearchParameter VarChar (100)
SET #SearchParameter = 'cricket'
SELECT DISTINCT ItemsTable.*
FROM #Itemstable ItemsTable
INNER JOIN udf_ItemParse (#SearchParameter, ',') udf
ON ItemsTable.Items LIKE '%' + udf.Item + '%'
SET #SearchParameter = 'cricket,tenis'
SELECT DISTINCT ItemsTable.*
FROM #Itemstable ItemsTable
INNER JOIN udf_ItemParse (#SearchParameter, ',') udf
ON ItemsTable.Items LIKE '%' + udf.Item + '%'
Why exactly are you using a database in the first place?
I mean : you are clearly not using it's potential. If you like using comma separated stuff, try a file.
In MySQL, create a fulltext index on your table:
CREATE FULLTEXT INDEX fx_mytable_items ON mytable (items)
and issue this query:
SELECT *
FROM mytable
WHERE MATCH(items) AGAINST ('cricket tennis' IN BOOLEAN MODE)