Basically I have two tables A and B. These are linked by unique ID's where the entries in B point to one entry in A. The entries in A and B also have a 'status' field denoting if the entry is active or not...
My questions is therefore; is it possible to link the status field of the entries in B and have them update, every time the 'status' field in A (pointed to by the unique ID) is updated? I could do this fairly easy with an SQL command however I'm wondering if there is a more automatic solution. Example:
table A
|------ID------|----status----|
| 1 | on |
| 2 | on |
|---------------|----------------|
table B
|-----eID------|------ID------|----status----|
| 1 | 1 | on |
| 2 | 1 | on |
| 3 | 2 | on |
|---------------|---------------|----------------|
I then run:
UPDATE `A` SET `status` = 'off' WHERE `ID` = 1;
And the result would be:
table A
|------ID------|----status----|
| 1 | off |
| 2 | on |
|---------------|---------------|
table B
|-----eID------|------ID------|----status----|
| 1 | 1 | off |
| 2 | 1 | off |
| 3 | 2 | on |
|---------------|---------------|----------------|
Is that possible?
Many Regards,
Andreas
i hope this trigger code can help u.
CREATE TRIGGER `abc` AFTER UPDATE ON `tablea` FOR EACH ROW BEGIN UPDATE tableb SET STATUS = new.status WHERE id = new.id;
END
Related
So here is my problem, how can i do this :
user with ID = 7 from table A with 3 columns want to insert data to table B with 4 columns but with the same id.
Table A :
| Id | name | password |
| 7 | john | password |
| 9 | mark | password |
| 12 | yuta | password |
Table B :
| Id | user_id | food | drink |
| 1 | 7 | oats | milk |
| 2 | 9 | fish | water |
| 3 | 12 | pear | fanta |
How can i achieve table b in 1 query? both id in both table are primary keys and im using mysql
here's the code i was trying to do :
INSERT INTO table_b SET food = :food, drink = :drink, ( user_id) SELECT a.id FROM table_a u WHERE EXISTS (SELECT * WHERE name = :name AND password = :password)
i know the query is wrong but thats the closest i can do. pls help thank you
You should just use a unique code to link them together.
you can have the code stored in a variable like this
$unique = time().rand(1000, 9999);
//You should have something like this 16659154332358
Create a column that will recieve this value in your database.
Now they have a relationship
I know it's a bad title, but I don't know how to describe my question in a line.
I want to store following information in my database.
+----+----------+-----------+-----------+
| id | name | cluster_1 | cluster_2 |
+----+----------+-----------+-----------+
| 1 | content_1| true| false |
| 2 | content_2| false| true |
| 3 | content_3| true| true |
+----+----------+-----------+-----------+
cluster_1=true means that the content exists on the cluster_1.
As some clusters may added or deleted, I want to store my cluster information in a new table "clusters", and indicate the relation between contents and clusters with a "content_cluster" table.
table contents
+----+----------+
| id | name |
+----+----------+
| 1 | content_1|
| 2 | content_2|
| 3 | content_3|
+----+----------+
table clusters
+----+----------+
| id | name |
+----+----------+
| 1 | cluster_1|
| 2 | cluster_2|
+----+----------+
table content_cluster
+----------+----------+
|content_id|cluster_id|
+----------+----------+
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 3 | 2 |
+----------+----------+
But, writing in this way, I don't know how to get a content which is on cluster_1 but isn't on cluster_2, or vice versa. I have to do this query frequently. So what is the efficient way to do this?
how to get a content which is on cluster_1 but isn't on cluster_2
in general
SELECT contents.name
FROM contents
JOIN content_cluster ON contents.id = content_cluster.content_id
LEFT JOIN clusters ON clusters.id = content_cluster.cluster_id
GROUP BY contents.name
HAVING SUM(clusters.name = 'cluster_1') -- not zero, may add ">0"
AND !SUM(clusters.name = 'cluster_2') -- zero, may replace NOT ("!") with "=0"
The following should work:
-- For cluster 1
INSERT INTO new_table (content_id, cluster_id)
SELECT old_table.content_id, 1
FROM old_table
WHERE old_table.cluster_1 = TRUE;
-- For cluster 2
INSERT INTO new_table (content_id, cluster_id)
SELECT old_table.content_id, 2
FROM old_table
WHERE old_table.cluster_2 = TRUE;
I have 2 tables in 1 database.
In the 2 tables there are several rows with the same contents.
table visitor
--------------------------
id | mytoken1 |
--------------------------
1 | token_abcd |
2 | token_efgh |
3 | token_ijkl |
4 | token_mnop |
--------------------------
table favorites
--------------------------
id | mytoken2 |
--------------------------
1 | token_abcd |
2 | token_efgh |
3 | token_ijkl |
4 | token_mnop |
5 | token_aaaa |
6 | token_bbbb |
7 | token_cccc |
8 | token_dddd |
--------------------------
How do I delete the mytoken2 column that is not in the mytoken1 column?
So in the example above I want to delete 4 rows of data, including:
token_aaaa
token_bbbb
token_cccc
token_dddd
I have tried to find a solution until I was dizzy but it has not been resolved, I hope someone will help me here ..
You can do using NOT IN
DELETE FROM favorites
WHERE token2 NOT IN (SELECT token1 FROM visitor)
You can use NOT EXISTS.
DELETE FROM favorites
WHERE NOT EXISTS (SELECT *
FROM visitor
WHERE visitor.mytoken1 = favorites.mytoken2);
JOIN also can be used here:
DELETE favorites.*
FROM favorites
LEFT JOIN visitor ON visitor.mytoken1 = favorites.mytoken2
WHERE visitor.id IS NULL;
Here you can test SQL query
+----+------------+------------+------------+----------+
| id | phone_no | join_date | city | blood_gp |
+----+------------+------------+------------+----------+
| 1 | 80077672xx | 1997-07-19 | Delhi | NULL |
| 2 | 80077642xx | 1998-07-19 | New Delhi | NULL |
| 3 | 80477642xx | 1999-07-19 | Mumbai | NULL |
| 4 | 80077654xx | 1997-05-31 | Kolkata | NULL |
+----+------------+------------+------------+----------+
I want to enter all the blood groups at once . Is there a way to do so ?
you can use single query with select and update
UPDATE table1 , (SELECT * FROM table2 where 1) src
SET table1.blood_gp = src.filed2 where 1 ;
if you want to insert multiple row data using single query then use this code
INSERT INTO yourtable (x,y,z) VALUES (a1,a2,a3), (b1,b2,b3);
or if you want to update one column value all filed then use this code
update yourtable set blood_gp = 'yourvalue' where 1;
if any problem then inform me
Just make an update query without where clause.
update table set blood_gp = 'value'
That's generalize query.
The goal here is to update and concatenate a text field from one table to another based on conditions. When a text col gets updated with some text from a user form, run After update trigger.
The trigger runs but updates all the columns not just the one that has changed.Trying to understand how to just update the correct row only.
Here's what i have so far-
SQLFiddle
| ID | SUBID | SWNOTES |
|----|-------|---------| Table 1
| 1 | 40 | test |
| 2 | 60 | |
| ID | SUBID | CONTENT | SWFLAG |
|----|-------|---------|--------|
| 1 | 40 | hello | 0 | Table 2
| 2 | 60 | nothing | 0 |
CREATE TRIGGER `updatecontentnotes` AFTER UPDATE ON `tab1`
FOR EACH ROW
BEGIN
IF New.swnotes <> OLD.swnotes
THEN
Update `tab2`
Inner Join `tab1` ON `tab2`.`subid` = `tab1`.`subid`
Set `tab2`.`swflag` = '1',`tab2`.`content` = CONCAT(`tab2`.`content`, `tab1`.`swnotes`)
Where `tab2`.`subid` = `tab1`.`subid` AND `tab2`.`swflag` = '0';
END IF;
END//
And if I update the table with say:
Update `tab1`
set `swnotes` = "new"
where `subid` = '60'
I get :
| ID | SUBID | CONTENT | SWFLAG |
|----|-------|------------|--------|
| 1 | 40 | hellotest | 1 |
| 2 | 60 | nothingnew | 1 |
Now I know it is doing what I am telling it to do. I want to update just the row that is updated. Thanks for any help on this.
Since the contents of your trigger will run for every row on tab1, you need to be more restrictive in your WHERE clause so that it will only affect the rows that have been updated. Right now it updates every row on tab2
Try adding this to your trigger SQL:
From:
Where `tab2`.`subid` = `tab1`.`subid` AND `tab2`.`swflag` = '0';
To:
Where `tab2`.`subid` = `tab1`.`subid` AND `tab2`.`swflag` = '0' AND `tab2`.`id` = OLD.id;
This produces the results that I think you are looking for:
| ID | SUBID | CONTENT | SWFLAG |
|----|-------|------------|--------|
| 1 | 40 | hello | 0 |
| 2 | 60 | nothingnew | 1 |
The updated SQLFiddle is here:
http://sqlfiddle.com/#!2/9fa2d2/1/0