I am working on a trigger which needs INSERT INTO with WHERE LIKE logic.
I have one table :
Tabel test;
idDocument = varchar(32) idUnit = varchar(3)
-----------------------------
| idDocument | idUnit |
-----------------------------
| AA/2021/KK | NULL |
| AA/2021/JJ | NULL |
| BB/2021/KK | NULL |
| CC/2021/JB | NULL |
-----------------------------
How to INSERT INTO using WHERE LIKE Condition and myquery still ERROR.
myquery :
INSERT INTO test ('idUnit') Values ('111') WHERE idDocument LIKE
'%KK%'
Normally to update existing rows with a new value you'd do something like this:
UPDATE test SET idUnit='111' WHERE idDocument LIKE '%KK%'
This will not insert data, it will only alter existing data.
Note:
INSERT is specifically for adding new rows of data
UPDATE is exclusively for updating existing rows with new data
You can't conditionally add new rows. You either add them or you don't. You can conditionally update or delete them.
Don't think about it in terms of inserting new data, always think in terms of rows and columns which is how SQL works.
Related
I want to add a new record in a table if duplicate value enters in a unique field. I don't want to update the existing one but want to add a new record by modifying the unique field value.
Is this possible in mysql?
EDIT:
Edited after user comment on this post:
You need write table locking on both of those two processes.
A WRITE lock has the following features:
The only session that holds the lock of a table can read and write data from the table.
Other sessions cannot read data from and write data to the table until the WRITE lock is released.
Also look at SQL UNIQUE Constraint
BEFORE EDIT:
Yes it is possible. And it took me awhile to figure it out. I build this on your input and compering values as test1, test2 etc, where test is always the same and has trailing number. As you specified.
It can be done as MySQL TRANSACTION in 4 steps.
Lets say you have table testT where name is unique to insure we have no doubles.
| id | name |
| --- | ----- |
| 1 | test1 |
| 2 | test3 |
And you want to insert a new item with name test1 we set is as:
SET #newName = 'test1';
Then we need to check if it already exists in table:
SELECT #check:=COUNT(*) FROM testT WHERE name = #newName;
We do a count here to get true or false and save it as #check here so we can compare it later. This will result into 1 row as test1 already exists in table.
Next we do another selection to get the highest number of test* and store it as #number, this next query selects all tests and does a SUBSTRING after 4 latter's giving us all numbers after first 4 latter's. (99999999999) numbers actually just to be sure we don't miss any but in our case result is only "3" because that is last record "test3" in table.
SELECT
#number:= SUBSTRING(name,5,99999999999)
FROM testT;
Now we can do an insert:
INSERT INTO testT(name)
VALUES
(
IF(#check = "", #newName , CONCAT(LEFT(#newName,4),RIGHT(#number,1)+1)
)
);
This tries to insert our #newName into table under IF condition, and that is if our #check is empty then he will insert #newName, if not it will take word test out of string and append a highest #number from earlier and add + 1 too it.
So result for #newName = 'test1' is below. If you change this into #newName = 'test3' result wold be same new insert test4.
**Schema (MySQL v5.7)**
SET #newName = 'test1';
---
**Query #1**
SELECT * FROM testT
ORDER BY id;
| id | name |
| --- | ----- |
| 1 | test1 |
| 2 | test3 |
| 3 | test4 |
---
And if you change it in ANY test* that number does not already exists it will insert it normally. In case below: #newName = 'test6'
SET #newName = 'test6';
**Query #1**
SELECT * FROM testT
ORDER BY id;
| id | name |
| --- | ----- |
| 1 | test1 |
| 2 | test3 |
| 3 | test6 |
This way an insert will always be made.
You can play with this here : View on DB Fiddle just by changing SET #newName = 'test6'
I am no expert and it took me couple of hours to figure this way out, as I wanted to know if this was even possible.
And I would appreciate if any other user can suggestion any other way or improve my method.
I'm trying to update one MySQL table based on information from another.
My original table looks like:
id | value
------------
1 | hello
2 | fortune
3 | my
4 | old
5 | friend
And the tobeupdated table looks like:
uniqueid | id | value
---------------------
1 | | something
2 | | anything
3 | | old
4 | | friend
5 | | fortune
I want to update id in tobeupdated with the id from original based on value (strings stored in VARCHAR(32) field).
The updated table will hopefully look like:
uniqueid | id | value
---------------------
1 | | something
2 | | anything
3 | 4 | old
4 | 5 | friend
5 | 2 | fortune
I have a query that works, but it's very slow:
UPDATE tobeupdated, original
SET tobeupdated.id = original.id
WHERE tobeupdated.value = original.value
This maxes out my CPU and eventually leads to a timeout with only a fraction of the updates performed (there are several thousand values to match). I know matching by value will be slow, but this is the only data I have to match them together.
Is there a better way to update values like this? I could create a third table for the merged results, if that would be faster?
I tried MySQL - How can I update a table with values from another table?, but it didn't really help. Any ideas?
UPDATE tobeupdated
INNER JOIN original ON (tobeupdated.value = original.value)
SET tobeupdated.id = original.id
That should do it, and really its doing exactly what yours is. However, I prefer 'JOIN' syntax for joins rather than multiple 'WHERE' conditions, I think its easier to read
As for running slow, how large are the tables? You should have indexes on tobeupdated.value and original.value
EDIT:
we can also simplify the query
UPDATE tobeupdated
INNER JOIN original USING (value)
SET tobeupdated.id = original.id
USING is shorthand when both tables of a join have an identical named key such as id. ie an equi-join - http://en.wikipedia.org/wiki/Join_(SQL)#Equi-join
It depends what is a use of those tables, but you might consider putting trigger on original table on insert and update. When insert or update is done, update the second table based on only one item from the original table. It will be quicker.
I have tgot the following table structure
mysql> desc test
-> ;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id | varchar(19) | NO | PRI | | |
| name | varchar(19) | YES | | NULL | |
| age | varchar(19) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.05 sec)
Initialy i have done an insert as shown
insert into test (id, name, age) values("1", "A", 19);
my requirement is that , i need to extract the age of id "1" and add some integer to the existing age
I have seen this below example , can tis be useful in my case ??
insert into test (id, name, age) values("1", "A", 30) on duplicate key update age=values(age)
I am using JAVA , i have symbols of 300 , for which i need to update contonouslly
Is it possible to do a select and update the existing column with new value in the same query ??
For example
how can i get the existing age 19 and add it with 30 in the same query for the id 1 ??
(This question has already been answered by Marc B in the comments section.)
Yes, the statement OP has posted will work just fine, because there is a primary key constraint on the id column, and INSERT ... ON DUPLICATE KEY will cause an UPDATE of the existing row.
To "add" the value being inserted to the value that already exists in the column, we'd assign an expression that does that operation to the column:
e.g.
insert into test (id, name, age) values("1", "A", 30)
on duplicate key update age = age + values(age)
^^^^^
Note that the only change required in OP statement is the reference to the existing column value and an addition operation.
N.B. If either the existing value in the column, or the new value being supplied in the INSERT statement is NULL, the result of the expression will be NULL. A different expression would be needed if this is undesired behavior.
This should work:
UPDATE test SET age=age+1 WHERE id=1;
I have this query:
mysql_query("
UPDATE users SET
`clicks_yesterday`=`clicks_today`,`clicks_today`=0)
My structure in my database looks like this:
My question is, how can I do so whenever I run the query above, clicks_yesterday get's the value of clicks_today?
Regards
That's how you do it. assignments in SQL are evaluated in the order encountered (e.g. left -> right). But if you want to be ENTIRELY sure that things are assigned properly, then split it into two queries:
UPDATE users SET clicks_yesterday = clicks_today;
UPDATE users SET clicks_today = 0;
For MySQL what you have written works. It is however different on different DBs so it's important to test.
These are my tests for this question
CREATE TABLE `duals` (
`one` int(11) DEFAULT NULL,
`two` int(11) DEFAULT NULL
);
insert into duals values (1, 2);
select * from duals;
+------+------+
| one | two |
+------+------+
| 1 | 2 |
+------+------+
update duals set one = two, two = 0;
select * from duals;
+------+------+
| one | two |
+------+------+
| 2 | 0 |
+------+------+
I'm trying to update one MySQL table based on information from another.
My original table looks like:
id | value
------------
1 | hello
2 | fortune
3 | my
4 | old
5 | friend
And the tobeupdated table looks like:
uniqueid | id | value
---------------------
1 | | something
2 | | anything
3 | | old
4 | | friend
5 | | fortune
I want to update id in tobeupdated with the id from original based on value (strings stored in VARCHAR(32) field).
The updated table will hopefully look like:
uniqueid | id | value
---------------------
1 | | something
2 | | anything
3 | 4 | old
4 | 5 | friend
5 | 2 | fortune
I have a query that works, but it's very slow:
UPDATE tobeupdated, original
SET tobeupdated.id = original.id
WHERE tobeupdated.value = original.value
This maxes out my CPU and eventually leads to a timeout with only a fraction of the updates performed (there are several thousand values to match). I know matching by value will be slow, but this is the only data I have to match them together.
Is there a better way to update values like this? I could create a third table for the merged results, if that would be faster?
I tried MySQL - How can I update a table with values from another table?, but it didn't really help. Any ideas?
UPDATE tobeupdated
INNER JOIN original ON (tobeupdated.value = original.value)
SET tobeupdated.id = original.id
That should do it, and really its doing exactly what yours is. However, I prefer 'JOIN' syntax for joins rather than multiple 'WHERE' conditions, I think its easier to read
As for running slow, how large are the tables? You should have indexes on tobeupdated.value and original.value
EDIT:
we can also simplify the query
UPDATE tobeupdated
INNER JOIN original USING (value)
SET tobeupdated.id = original.id
USING is shorthand when both tables of a join have an identical named key such as id. ie an equi-join - http://en.wikipedia.org/wiki/Join_(SQL)#Equi-join
It depends what is a use of those tables, but you might consider putting trigger on original table on insert and update. When insert or update is done, update the second table based on only one item from the original table. It will be quicker.