I have 2 tables, called tb_compulsory_savings and tb_time_deposits
for tb_compulsory_savings
form_no | badge_id | compulsory_savings | transaction_date
1 | 090802 | 50000 | 2016-05-20 13:10:11
2 | 090801 | 50000 | 2016-05-20 13:15:15
for tb_time_deposits
form_no | badge_id | time_deposits | transaction_date | period | status
1 | 090802 | 100000 | 2016-05-20 13:20:44 | May-2016 | closed
Now I want to query that 2 table to be like this:
badge_id | compulsory_savings | time_deposits
090802 | 50000 | 100000
090801 | 50000 | null
So, if badge_id: 090801 is not existed in tb_time_deposits, it will display null.
I have tried LEFT JOIN, RIGHT JOIN, UNION but still the display is not as I want.
Looks like you're looking for a left join:
SELECT cs.badge_id, cs.compulsary_savings, td.time_deposits
FROM tb_compulsory_savings cs
LEFT JOIN tb_time_deposits td ON cs.badge_id = td.badge_id
Try this query might work :
SELECT badge_id,compulsory_savings,time_deposit FROM
tb_compulsory_savings LEFT JOIN tb_time_deposits ON
tb_compulsory_savings.badge_id=tb_time_deposits.badge_id;
Related
I have an SQL model (MySQL v8.0.20) that describes a physical card with 1 or 2 faces. Because card faces can appear on multiple physical cards, I've modeled this as a many-many relationship using the join table cardFaces.
I'm now trying to get a list of distinct front facing cards. That is if a card has only 1 face, it would be represented once, if it has 2 faces, it would be represented twice (once for each side front facing).
Input
The join table currently looks like this (simplified for question):
SELECT * FROM cardFaces;
+----+--------+--------+
| id | cardId | faceId |
+----+--------+--------+
| 1 | A | 1 |
| 2 | B | 2 |
| 3 | B | 3 |
+----+--------+--------+
Expected Output
The result I'm expecting to achieve is this:
+--------+-------------+------------+
| cardId | frontFaceId | backFaceId |
+--------+-------------+------------+
| A | 1 | NULL |
| B | 2 | 3 |
| B | 3 | 2 |
+--------+-------------+------------+
Current Output
I've only gotten so far as self-joining and removing duplicates, but I can't figure out how to introduce NULL as the backFaceId for cards with only 1 face.
SELECT frontFace.cardId, frontFace.faceId frontFaceId, backFace.faceId backFaceId
FROM cardFaces frontFace
LEFT JOIN cardFaces backFace
ON frontFace.cardId = backFace.cardId
WHERE backFace.id != frontFace.id;
+--------+-------------+------------+
| cardId | frontFaceId | backFaceId |
+--------+-------------+------------+
| B | 2 | 3 |
| B | 3 | 2 |
+--------+-------------+------------+
Move the where condition to the on clause:
SELECT frontFace.cardId, frontFace.faceId frontFaceId, backFace.faceId backFaceId
FROM cardFaces frontFace LEFT JOIN
cardFaces backFace
ON frontFace.cardId = backFace.cardId AND
backFace.id <> frontFace.id;
NULLs fail almost all comparisons, including <>, turning the outer join into an inner join.
Could anybody enlighten me with this question?
Let's assume I have a table with several records like this:
+--------------+--+
| ID room time | |
+--------------+--+
| 1 1 10:00 | |
| 2 2 10:01 | |
| 3 1 10:01 | |
| 4 1 10:02 | |
| 5 1 10:03 | |
| 6 1 10:04 | |
| 7 2 10:02 | |
+--------------+--+
I would like to get the count of time of room 1 only when it is continuous.
The result for this particular table should be:
+--------------+
| id room time |
+--------------+
| 1 1 00:03 |
+--------------+
Thanks in advance.
You can join a table against itself to achieve that:
Let's say the name of the table is tbl. My query won't quite be 100% right because I don't know what your data type is for time, but the concept is there.
The A table must have an ID less than the one with the B id, but have the same room.
The C table represents records a check that there is no IDs between A and B for a different room, that's why C.ID is NULL
SELECT A.ROOM, MAX(B.TIME-A.TIME) FROM tbl A
INNER JOIN tbl B on A.room=B.room and A.ID<B.ID
LEFT OUTER JOIN tbl C on A.room<>B.room and A.ID<C.ID and C.ID<B.ID
WHERE C.ID IS NULL
GROUP BY a.room
I am working on a product sample inventory system where I track the movement of the products. The status of each product can have a status of "IN" or "OUT" or "REMOVED". Each row of the table represents a new entry, where ID, status and date are unique. Each product also has a serial number.
I need help with a SQL query that will return all products that are currently "OUT". If I simply just select SELECT * FROM table WHERE status = "IN", it will return all products that ever had status IN.
Every time product comes in and out, I duplicate the last row of that specific product and change the status and update the date and it will get a new ID automatically.
Here is the table that I have:
id | serial_number | product | color | date | status
------------------------------------------------------------
1 | K0T4N | XYZ | silver | 2016-07-01 | IN
2 | X56Z7 | ABC | silver | 2016-07-01 | IN
3 | 96T4F | PQR | silver | 2016-07-01 | IN
4 | K0T4N | XYZ | silver | 2016-07-02 | OUT
5 | 96T4F | PQR | silver | 2016-07-03 | OUT
6 | F0P22 | DEF | silver | 2016-07-04 | OUT
7 | X56Z7 | ABC | silver | 2016-07-05 | OUT
8 | F0P22 | DEF | silver | 2016-07-06 | IN
9 | K0T4N | XYZ | silver | 2016-07-07 | IN
10 | X56Z7 | ABC | silver | 2016-07-08 | IN
11 | X56Z7 | ABC | silver | 2016-07-09 | REMOVED
12 | K0T4N | XYZ | silver | 2016-07-10 | OUT
13 | 96T4F | PQR | silver | 2016-07-11 | IN
14 | F0P22 | DEF | silver | 2016-07-12 | OUT
This query will give you all the latest records for each serial_number
SELECT a.* FROM your_table a
LEFT JOIN your_table b ON a.serial_number = b.serial_number AND a.id < b.id
WHERE b.serial_number IS NULL
Below query will give your expected result
SELECT a.* FROM your_table a
LEFT JOIN your_table b ON a.serial_number = b.serial_number AND a.id < b.id
WHERE b.serial_number IS NULL AND a.status LIKE 'OUT'
There are two good ways to do this. Which way is best,in terms of performance, can depend on various factors, so try both.
SELECT
t1.*
FROM table t
LEFT OUTER JOIN table later_t
ON later_t.serial_number = t.serial_number
AND later_t.date > t.date
WHERE later_t.id IS NULL
AND t.status = "OUT"
Which column you check from later_t for IS NULL does not matter, so long as that column is declared NOT NULL in the table definition.
The other logically equivalent method is:
SELECT
t.*
FROM table t
INNER JOIN (
SELECT
serial_number,
MAX(date) AS date
FROM table
GROUP BY serial_number
) latest_t
ON later_t.serial_number = t.serial_number
AND latest_t.date = t.date
WHERE t.status = "OUT"
For each of these queries, I strongly suggest the following index:
ALTER TABLE table
ADD INDEX `LatestSerialStatus` (serial_number,date)
I use this type of query a lot in my own work, and have the above index as the primary key on tables. Query performance is extremely fast in such cases, for these type of queries.
See also the documentation on this query type.
I'm having BookTable in database (with foregin hey LibID):
| BookID | BookName | BookPrice | LibID |
-------------------------------------------
| 1 | Book_1 | 200 | 1 |
| 2 | Book_2 | 100 | 1 |
| 3 | Book_3 | 300 | 2 |
| 4 | Book_4 | 150 | 4 |
and also LibraryTable:
| LibID | LibName | LibLocation |
-----------------------------------
| 1 | Lib_1 | Loc_1 |
| 2 | Lib_2 | Loc_2 |
| 3 | Lib_3 | Loc_3 |
| 4 | Lib_4 | Loc_4 |
I need to write SQL query that will return be the info about the library and number of books for that library:
| LibID | LibName | NumberOfBooks|
------------------------------------
| 1 | Lib_1 | 2 |
| 2 | Lib_2 | 1 |
| 3 | Lib_3 | 0 |
| 4 | Lib_4 | 1 |
It should be one SQL query, probably with nested queries or joins.. Not sure how the query should look like:
SELECT L.LibID AS LibID, L.LibName AS LibName, COUNT(B) AS NumberOfBooks
FROM LibraryTable L, BookTable B
WHERE L.LibID = B.LibID
Will that work?
No, this query will not work. COUNT aggregates data, so you must explicitely tell the DBMS for which group of data you want the count. In your case this is the library (you want one result record per library).
COUNT's parameter is a column, not a table, so change this to * (i.e. count records) or a certain column (e.g. LibID).
The join syntax you are using is valid, but deprecated. Use explicit joins instead. In your case an outer join would even show libraries that have no books at all, if such is possible.
select l.libid, l.libname, count(b.libid) as numberofbooks
from librarytable l
left outer join booktable b on b.libid = l.libid
group by l.libid;
You could also do all this without a join at all and get the book count in a subquery instead. Then you wouldn't have to aggregate. That's way simpler and more readable in my opinion.
select
l.libid,
l.libname,
(select count(*) booktable b where b.libid = l.libid) as numberofbooks
from librarytable l;
SELECT lt.LibID AS LibID, lt.LibName AS LibName, count(*) AS NumberOfBooks
FROM BookTable AS bt
LEFT JOIN LibraryTable AS lt ON bt.LibID = lt.LibID
GROUP BY bt.LibID
I am trying to join two tables and only select the dealers that did not have their promo code used on any order.
How can I do this?
I'm trying this below, but it's not working right. In the example I want to get just Bob, since his promo_code hasn't been used in any orders.
SELECT d.`name`
FROM z_dealer d
LEFT OUTER JOIN z_order o ON (d.promo_code = o.promo_code)
AND o.promo_code IS NULL
Here are my tables...
mysql> select * from z_dealer;
+----+------+------------+
| id | name | promo_code |
+----+------+------------+
| 1 | John | holiday |
| 2 | Suzy | special |
| 3 | Bob | laborday |
+----+------+------------+
mysql> Select * from z_order;
+----+-------+------------+
| id | total | promo_code |
+----+-------+------------+
| 1 | 10 | holiday |
| 2 | 20 | special |
| 3 | 15 | holiday |
| 4 | 45 | special |
+----+-------+------------+
SELECT d.`name` FROM z_dealer d LEFT JOIN z_order o ON (d.promo_code = o.promo_code) WHERE o.promo_code IS NULL
Have you tried INNER JOIN? or You can try IN like this :
SELECT d.name
FROM z_dealer d
WHERE d.promo_code not in( SELECT promo_code FROM z_order)
I'm not entirely sure why it's not working in your example code. I've created the same tables locally and when I run the script you provided I get the single 'Bob' answer.
SELECT d.name
FROM z_dealer d
LEFT OUTER JOIN z_order o ON (d.promo_code = o.promo_code)
AND o.promo_code IS NULL
What results are you seeing exactly?