Show values from a column, using values from another column as conditions - mysql

I have a table called "fisketur" that looks like this:
I have a table called "plads" that looks like this:
How can I make it so that I only get the values from "plads.navn" that have a "plads.id" that corresponds to a specific month of the year (as found in the "fisketur" table)?
This is what I tried (getting all "plads.navn" that correspond to a "fisketur" taking place in october (month=10):
The output is correct, BUT I would like to set the the whole output column from line 92 (select plads_id from lystfisker.fisketur where month(dato)=10;) as a condition, and not have to set the output values manually as done in line 93.
Any help is greatly appreciated,
Best regards.


You can do it using subquery :
select navn
from lystfisker.plads
where plads_id in ( select plads_id
from lystfisker.fisketur
where month(dato) = 10
);
Or using an inner join
select navn
from lystfisker.plads p
inner join lystfisker.fisketur f on f.plads_id = p.plads_id
where month(f.dato) = 10

Related

SELECT statement inside a CASE statement in SNOWFLAKE

I have a query where i have "TEST"."TABLE" LEFT JOINED to PUBLIC."SchemaKey". Now in my final select statement i have a case statement where i check if c."Type" = 'FOREIGN' then i want to grab a value from another table but the table name value i am using in that select statement is coming from the left joined table column value. I've tried multiple ways to get to work but i keep getting an error, although if i hard code the table name it seems to work. i need the table name to come from c."FullParentTableName". Is what i am trying to achieve possible in snowflake and is there a way to make this work ? any help would be appreciated !
SELECT
c."ParentColumn",
c."FullParentTableName",
a."new_value",
a."column_name"
CASE WHEN c."Type" = 'FOREIGN' THEN (SELECT "Name" FROM TABLE(c."FullParentTableName") WHERE "Id" = 'SOME_ID') ELSE null END "TestColumn" -- Need assistance on this line...
FROM "TEST"."TABLE" a
LEFT JOIN (
select s."Type", s."ParentSchema", s."ParentTable", s."ParentColumn", concat(s."ParentSchema",'.','"',s."ParentTable",'"') "FullParentTableName",s."ChildSchema", s."ChildTable", trim(s."ChildColumn",'"') "ChildColumn"
from PUBLIC."SchemaKey" as s
where s."Type" = 'FOREIGN'
and s."ChildTable" = 'SOMETABLENAME'
and "ChildSchema" = 'SOMESCHEMANAME'
) c
on a."column_name" = c."ChildColumn"
Thanks !

In Snowflake you cannot dynamically use the partial results as tables.
You can use a single bound value via identifier to bind a value to table name
But you could write a Snowflake Scripting but it would need to explicitly join the N tables. Thus if you N is fixed, you should just join those.

Group rows but keep values where not null

I am trying to group rows in MySQL but end up with a wrong result.
My DB looks like this:
I'm using this query:
SELECT
r_id, va_id,va_klasse,va_periode,
1va_mer,1va_hjem,1va_mot,1va_bil,1va_fit,1va_hand,1va_med,1va_fra,
2va_mer,2va_hjem,2va_trae,2va_bil,2va_sty,2va_mus,2va_med,2va_fra,
3va_mer,3va_hjem,3va_mot,3va_bil,3va_pima,3va_nat,3va_med,3va_fra,
va_lock, va_update
FROM o6hxd_valgfag
WHERE va_klasse IN('7A','7B','7C','8A','8B','8C','9A','9B','9C')
GROUP BY va_id
ORDER BY va_klasse,va_name
This produces a wrong result, where one row is returned with only the first three numbers 123 and not the ones from row two and three.
What I would like is a result where the numbers 123, 321 and 132 are gathered in one line.
I can explain more detailed if this isn't sufficient.

If across those fields there should only be ever one value, you should really have them all in the same record and go about fixing it to insert and update the same record.
Ie I am aware that you database isn't designed correctly
However
To dig you out, you could give this a crack, I suppose.
SELECT
r_id, va_id,va_klasse,va_periode,
MAX(1va_mer),MAX(1va_hjem),MAX(1va_mot),MAX(1va_bil),MAX(1va_fit),MAX(1va_hand),MAX(1va_med),MAX(1va_fra),
MAX(2va_mer),MAX(2va_hjem),MAX(2va_trae),MAX(2va_bil),MAX(2va_sty),MAX(2va_mus),MAX(2va_med),MAX(2va_fra),
MAX(3va_mer),MAX(3va_hjem),MAX(3va_mot),MAX(3va_bil),MAX(3va_pima),MAX(3va_nat),MAX(3va_med),MAX(3va_fra),
va_lock, va_update
FROM o6hxd_valgfag
WHERE va_klasse IN('7A','7B','7C','8A','8B','8C','9A','9B','9C')
GROUP BY va_id
ORDER BY va_klasse,va_name

Your query will not work as intended. Think about this use-case:
what if for row1 (r_id =9), the fields 2va_sty, 2va_mus, 2va_med are not empty and has values?
In such case what should your desired output be? It certainly cannot be the numbers 123, 321 and 132 gathered in one line. Group by is usually used if you want to use aggregate functions executed against a certain field value, in your case va_id.

Not a solution to your problem but i think a better query would be like this (because of the not named columns in the group by clause https://dev.mysql.com/doc/refman/5.5/en/group-by-handling.html):
SELECT
aa.r_id, aa.va_id, aa.va_klasse, aa.va_periode,
aa.1va_mer, aa.1va_hjem, aa.1va_mot, aa.1va_bil, aa.1va_fit, aa.1va_hand, aa.1va_med, aa.1va_fra,
aa.2va_mer, aa.2va_hjem, aa.2va_trae, aa.2va_bil, aa.2va_sty,2va_mus, aa.2va_med, aa.2va_fra,
aa.3va_mer, aa.3va_hjem, aa.3va_mot, aa.3va_bil, aa.3va_pima, aa.3va_nat, aa.3va_med, aa.3va_fra,
aa.va_lock, aa.va_update
FROM o6hxd_valgfag AS aa
INNER JOIN (
SELECT va_id
FROM o6hxd_valgfag
GROUP BY va_id
) AS _aa
ON aa.va_id = _aa.va_id
WHERE aa.va_klasse IN ('7A','7B','7C','8A','8B','8C','9A','9B','9C')
ORDER BY aa.va_klasse, aa.va_name;

How to write update query using 2 tables and conditions

I am trying to update/revise the department names in a table called "DEPART_NAMES_AS_SUBMITTED" using another table called "DEPART_NAMES_REQUIRED." I would like this update to occur only if the line numbers in "DEPART_NAMES_AS_SUBMITTED" are within the line number range [LOW] [HIGH] in the second table called "DEPART_NAMES_REQUIRED." If the line number is less/more than the [LOW] [HIGH] range the department name should remain the same. I have unsuccessfully tried numerous SQLs including the following:
UPDATE DEPT_NAMES_SUBMITTED INNER JOIN DEPT_NAMES_REQUIRED ON(DEPT_NAMES_SUBMITTED.LINE_NUMBER = DEPT_NAMES_REQUIRED.HIGH) AND (DEPT_NAMES_SUBMITTED.LINE_NUMBER = DEPT_NAMES_REQUIRED.LOW) SET DEPT_NAMES_SUBMITTED.DEPART_NAME = [DEPT_NAMES_REQUIRED].[DEPART_NAME]
WHERE (((DEPT_NAMES_REQUIRED.LINE_NUMBER) Between [low] And [high]));
Thank you for taking the time to read and answer this question.

I think your query is fine if you remove the square braces and put in the right logic:
UPDATE DEPT_NAMES_SUBMITTED ns INNER JOIN
DEPT_NAMES_REQUIRED hr
ON ns.LINE_NUMBER <= nr.HIGH AND
ns.LINE_NUMBER >= nr.LOW
SET ns.DEPART_NAME = nr.DEPART_NAME;
Notice that table aliases make the query easier to write and to read.

MySQL Locate Duplicates between two table with similar column

Using this question's answer. I'm trying to find duplicate records between two tables by the column names matrix_unique_id and Matrix_Unique_ID in each table and then display the full address. The Full address columns are formatted differently from each other in each table so I cannot use that as a comparison. I'm getting an "unknown column fort_property_res.matrix_unique_id" error but everything looks okay?
So two questions:
Will this query find duplicates correctly?
Why the unknown column error?
SQL query:
SELECT matrix_unique_id, full_address
FROM fort_property_res
INNER JOIN (
SELECT Matrix_Unique_ID, FullAddress
FROM sunshinemls_property_res
GROUP BY FullAddress
HAVING count(fort_property_res.matrix_unique_id) > 1
) dup ON fort_property_res.matrix_unique = sunshinemls_property_res.Matrix_Unique_ID

The solution you're trying to copy is a totally different case. You have two tables and (it looks like) a convenient matrix_unique_id to join on, so this is much easier:
SELECT fort.matrix_unique_id, fort.full_address AS fortAddress, sun.FullAddress AS sunAddress
FROM fort_property_res fort, sunshinemls_property_res sun
WHERE fort.matrix_unique_id = sun.Matrix_Unique_ID

Correct MySQL JOIN format to avoid nested SELECT

I have two separate SELECT statements:
SELECT VCe.VId FROM `VCe` WHERE `YId` = 9007 AND `MaId` =76 AND `MoId` = 2851
SELECT r_pts.p_id FROM r_pts WHERE r_pts.v_id IN (57202, 57203, 69597, 82261, 82260, 69596, 69595, 82259)
When they are run separately they both complete in under .05sec however when I nest the first one within the second, it dramatically increases to 3.3sec.
I would like to do a join so that I can get the output from the second SELECT using the first select as the result set for the IN() but I cannot figure out how to include WHERE conditions in a JOIN.
Edit: Also what is the correct syntax to do a join as I am requesting?
Thanks for your help, its appreciated!

Equivalent to MattMcKnight's query whilst illustrating "how to include WHERE conditions in a JOIN":
SELECT r.p_id
FROM r_pts r
INNER JOIN VCe v
ON v.VId = r.v_id
AND
v.YId = 9007
AND
v.MaId = 76
AND
v.MoId = 2851

SELECT r_pts.p_id FROM r_pts, 'VCe' WHERE r_pts.v_id = VCe.VId AND VCe.YId = 9007 AND VCe.MaId =76 AND VCe.MoId = 2851
The basic goal of a join is to describe how the two tables relate. I inferred from your example that the v_id column in the r_pts table was a foreign key pointing to the VId primary key in the VCe table. When you add a term in the query (such as "r_pts.v_id = VCe.VId") that has a field from each table you wish to join, that tells the database how to match up the rows between the tables to make "virtual rows" that contain the columns from both tables. Your other query terms limit which rows are included in the result set.