How Oracle insert statement work - oracle

Suppose I have a tableX with the following columns accordingly -
id | name | description | contact_no
Now if I perform an insert operation
insert into tableX(id, contact_no, name, description) value(?,?,?,?)
[note the order of the coulmns]
In which order oracle will insert each column values?
i) according to the insert statement
ii) according to the column order in the tableX
iii) or oracle sort the columns alphabetically [id, contact_no, description, name] and put them accordingly.

It will put values based on column list:
insert into tableX(id, contact_no, name, description)
-- 1st 2nd 3rd 4th
values(1st, 2nd, 3rd, 4th);
If you omit column list then you will get "blind insert"(common anti-pattern).

According to the column you specified in the insert from left to right
insert into tableX(id, contact_no, name, description) value(1,2,3,4)

Related

How do you Save calculated columns from one table to another table using Oracle APEX?

As the question states, I'm trying to save calculated data, that is the result of a select statement, to another table. In this Image, the column with green outline is a database column and the columns with red outline are calculated based on that column, I want to save the Red outlined columns to another table where the column names would be same.
This looks like a classic report. Is it? If so, it is result of a select statement. As it calculates all values you're interested in, you'd use it in an insert statement. For example, you could create a button and create a process that fires when that button is pressed. It would then
insert into target_table (emp_id, salary, house_rent, ...)
select emp_id, ... whatever you select in report's query
from ...
However: data changes. What will you do when something - that is used to calculate those values - is changed? Will you delete those rows and insert new ones? Update existing values? Add yet another row?
If you'd update existing values, consider using merge as it is capable of inserting rows (in when not matched clause, in your case) , as well as updating rows (in when matched). That would look like this:
merge into target_table t
using (select emp_id, ... whatever you select in report's query
from ...
) x
on (t.emp_id = x.emp_id)
when matched then update set
t.salary = x.salary,
t.house_rent = x.house_rent,
...
when not matched then insert (emp_id, salary, house_rent, ...)
values (x.emp_id, x.salary, x.house_rent, ...);
You can use the INSERT INTO SELECT statement - plenty of examples available on google
INSERT INTO another_table (
emp_id,
col1,
col2
)
SELECT emp_id,
calculated_col1,
calculated_col2
FROM first_table

PL\SQL - Fetch values from table and Item - Oracle Apex

I need to insert data of one table to another table. All the values are from the table except one SO_ID. It is coming from the Item on the page. How do I do it?
insert into T_SORDER_ITEM_INWARD
(
select sd.ID, SO_ID
into :P25_SO_ID, sd.STOCK_ID,sd.ITEM_ID,sd.UOM_ID,
sd.ITEM_CONDITION_ID,sd.ORIGINAL,sd.ACTUAL,sd.WIDTH,sd.LENGTH,sd.STOCKQTY,
sd.KANTA,sd.RATE,sd.PACKET, sd.LABEL_METER, sd.EXCESS_SHORT,sd.LOCATION_ID,
sd.CLIENT_INITIAL, sd.FIN_YEAR, sd.SERIAL_NO
from T_STOCK_DETAIL sd join t_stock_master sm
on sd.stock_id = sm.stock_id
where sm.customer_id = p25_customer
)
A simplified example:
insert into another_table (id, name, location)
select :P25_SO_ID,
t.name,
t.location
from this_table t
Always name all columns you're inserting into (first line in my example).
Your query is impossible to understand. Not just because syntax is wrong, but because we have no idea which column is supposed to get which value.

Calculating difference between a row and its next row (same column) after sorting them based on the same column

How to calculate difference between a row and its next row (same column) after sorting them based on the same column.
select col_name - lead(col_name) over (order by col_name) from table_name
will do what you need. The result for the largest value in the column should be NULL (since there is no "next row" for that row).
If you also separate by another column, for example by employee_id, you need a partition clause as well, as in
...over (partition by employee_id order by column_name)...

In hive, is there a way to specify between which columns to add a new column to?

I can do
ALTER TABLE table_name ADD COLUMNS (user_id BIGINT)
to add a new column to the end of my non-partition columns and before my partition columns.
Is there any way to add a new column to anywhere among my non-partition columns?
For example, I would like to put this new column user_id as the first column of my table
Yes it is possible to change the location of columns but only after adding it in the table using CHANGE COLUMN
In your case, first add the column user_id to the table with below command:
ALTER TABLE table_name ADD COLUMNS (user_id BIGINT);
Now to make user_id column as the first column in your table use change column with FIRST clause:
ALTER TABLE table_name CHANGE COLUMN user_id user_id BIGINT first;
This will move the user_id column to the first position.
Similarly you can use After instead of first if you want to move the specified column after any other column. Like say, I want to move dob column after user_id column. Then my command would be:
ALTER TABLE table_name CHANGE COLUMN dob dob date AFTER user_id;
Please note that this commands changes metadata only. If you are moving columns, the data must already match the new schema or you must change it to match by some other means.
Ah, here's the explanation for why you listed user_id twice (it's not a type):
// Next change column a1's name to a2, its data type to string, and put it after column b.
ALTER TABLE test_change CHANGE a1 a2 STRING AFTER b;
// The new table's structure is: b int, a2 string, c int.
No, it is not possible.
One solution is to create new table using "CREATE TABLE AS SELECT" approach and drop older one.

sql statement to select and insert one value from one table rest from outside the tables

I have two db2 tables, table one contains rows of constant data with id as one of the columns. second table contains id column which is foreign key to id column in first table and has 3 more varchar columns.
I am trying to insert rows into second table, where entry into id col is based on a where clause and the remaining columns get values from outside.
table1 has columns id, t1c1, t1c2, t1c3
table2 has columns id, t2c1, t2c2, t2c3
to insert into table2, I am trying this query:
insert into table2 values
(select id from table1 where t1c2 like 'xxx', 'abc1','abc2');
I know it is something basic I am missing here.
Please help correcting this query.

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