I need to update ID column in table after Insert.
ID is varchar and auto-increment. I need to update the value of ID .
Eg.
when we insert a column and the ID value is supposed to be 10, so after the trigger is executed ID value should be updated to 10F.
Based on your comments, you do not need to modify the ID column permanently, which you should never do anyway, but only during certain queries.
To use the ID to distinguish which table a row came from in a join s also a bag idea - IDs should not have any information “encoded” in them: They should be meaningless unique values.
If your design is broken and you absolutely must modify the ID:
select concat(id, 'F') as ID, other_columns from tableA
union all
select ID, other_columns from tableB
or better, introduce an extra column that indicates which table each row came from:
select *, 'F' as origin from tableA
union all
select *, '' as origin from tableB
Related
I need to create an identical copy of many records in a table. The table has a PK id, which of course will be different, in the freshly-copied records.
For example, let's say i have a scrum_card table, with the following non-unique columns: name, description, board_id
I have a dynamic array of id's of records, which i wish to duplicate: [34,56,32,3445,...]
How do i tell MYSQL, to fetch the data from all those records, and make a batch-insert of those same records?
In "human" syntax it would look something like this: "Select all columns(besides id) from scrum_card where the id's are [array of id's], then duplicate each found record".
Use INSERT INTO ... SELECT... and in the list of columns do not include the id:
insert into scrum_card(name, description, board_id)
select name, description, board_id
from scrum_card
where id in (34,56,32,3445,...)
You can use INSERT using a SELECT result set as the source, instead of a set of literal row tuples with VALUES(...).
INSERT INTO new_table (id, col1, col2, col3...)
SELECT NULL, col1, col2, col3...
FROM old_table
WHERE id IN (34,56,32,3445,...)
Using NULL in place of the id column in the SELECT will return NULL for each row, which will cause new_table to generate a new id value.
But SQL does not have any way to do a wildcard like "all columns except id," besides you typing the column names in.
I want to insert values from different sources. For example
insert into a (('id','name','add'),'college')
select from b where id = 1,'abc'
Here there is no timestamp field in table b
I would rewrite your query as follows:
insert into a (id, name, add, college)
select id, name, add, 'abc' from b where id = 1
With this query, the 4th column in a will be assigned a constant value of 'abc'.
I've got the following table:
productId price
1 price_value1
2 price_value2
3 price_value3
I would like to insert a new product into the table and assign it a new productId. In this case its value equals to 4.
So I want my new table to look like so:
productId price
1 price_value1
2 price_value2
3 price_value3
4 price_value4
So as far as I understand, in order to do that I have to somehow retrieve the max value of productId and insert it using INSERT INTO mytable VALUES (productId + 1, price_value4).
But how do I find out the maximum value of productId?
I tried INSERT INTO mytable VALUES (SELECT MAX(productId) + 1 FROM mytable, price_value4) but it didn't work.
This should Work:
Select the max(productID) and price_value4 as a columns from mytable and insert the result.
INSERT INTO mytable (SELECT MAX(productId) + 1, 'price_value4' FROM mytable);
However, if you are not going to jump some number you can just add an auto increment id key to product_id and then you will have only to insert the price, the product ID will be incremented automatically..
This will do so :
ALTER TABLE mytable
MODIFY COLUMN `productId` INT(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
you can change INT(10) with the INT(5) for example depanding on the size you want to give to your productId column
EDIT :
In return to the OP question in comments why his solution wouldn't work
Some suggetions says you have to make the SELECT statment in insert always between parenthesis
INSERT INTO mytable VALUES ( (SELECT MAX(ID)+1 FROM mytable) , price_value4)
.. In my Case it Return
(1093): You can't specify target table
'mytable' for update in FROM clause
AND HERE IS WHY (Quoting From the documentation)
When selecting from and inserting into the same table, MySQL creates
an internal temporary table to hold the rows from the SELECT and then
inserts those rows into the target table. However, you cannot use
INSERT INTO t ... SELECT ... FROM t when t is a TEMPORARY table,
because TEMPORARY tables cannot be referred to twice in the same
statement
BUT there is away to overcome by using a query instead of the table itself in the FROM, which has the effect of copying the requested table values instead of referencing the one that you are updating..
INSERT INTO mytable VALUES (
(SELECT MAX(ID)+1 FROM (SELECT * FROM mytable ) as mytmp ),
'price_value4');
OR (Quoting From the documentation)
To avoid ambiguous column reference problems when the SELECT and the
INSERT refer to the same table, provide a unique alias for each table
used in the SELECT part, and qualify column names in that part with
the appropriate alias.
INSERT INTO mytable Values ( (SELECT MAX(ID)+1 FROM mytable as mytmp) , 'price_value4')
This is a duplicate question. In order to take advantage of the auto-incrementing capability of the column, do not supply a value for that column when inserting rows.
A simple syntax to create table
CREATE TABLE Product (
productId MEDIUMINT NOT NULL AUTO_INCREMENT,
price INT NOT NULL,
PRIMARY KEY (productid)
);
While inserting supplied default or leave column as blank or supplied value as NULL. Take a look at below code snippet.
INSERT INTO Product (price) VALUES
('10'),('20'),('4'),
('30');
refer this link
i got 2 tables that i want to combine its data.
the id is my key field (incremental and distinct).
table 1 and table 2 field description for example:
id - name - value
i want to insert all of table 2 data into table 1, they have different data but in some rows the same id.
so when i try to:
INSERT INTO ladatabase.table2 SELECT * from ladatabase.table1;
i get duplicate entry error.
please help me to suggest how can i solve it and combine the data with different id values for the new data.
Alex.
here are 2 ways:
first you can use if the id AUTO INCREMENT
INSERT INTO ladatabase.table2
SELECT '', name, value from ladatabase.table1;
or you find the first free ID and add it
INSERT INTO ladatabase.table2
SELECT id+555 , name, value from ladatabase.table1;
No insert all fields (exclude 'id'-field from SELECT):
INSERT INTO ladatabase.table2 SELECT name,value from ladatabase.table1;
You need to copy all but the ID column, and it will assign new IDs. You need to list all the other columns explicitly. Leaving out the ID column will cause it to get its default value, which are sequential IDs for an auto_increment field.
INSERT INTO table2 (col2, col3, col4, ...)
SELECT col2, col3, col4, ...
FROM table1
I am trying to fetch all rows from a particular table if value found in any column of the particular table.
you can just use IN. eg
SELECT *
FROM tbName
WHERE yourValue IN (column1, column2, column3, ....)
You can probably use the EXISTS to do your job.
Below query will get the stores name only if city 2 has a name.
SELECT store_name FROM stores WHERE EXISTS (SELECT name FROM cities WHERE id = 2);