id value
1 a
2 b
3 c
How do i add second value 'z' to id=1 (separated by comma)?
id value
1 a,z
2 b
3 c
and how to remove the 'z' now if i have that final table?
You can use update:
update t
set value = concat(value, ',z')
where id = 1;
To answer your secondary question, yes.
If you run Select value from table where id = 1 it will return a,z. that means that if you are going to use it again in queries, you will quite possibly need to utilize a Split() type function, dependent on what you're doing with it.
The best and simplest way to do this is the following query according to me :
update table1 set value = concat(value,'z') where id = 1
where : Table1 is the name of your table.
Related
I have table like this :
ID | key | value
1 | A1 |o1
1 | A2 |o2
1 | A3 |o3
2 | A1 |o4
2 | A2 |o5
3 | A1 |o6
3 | A3 |o7
4 | A3 |o8
I want to write a oracle query that can filter value column based on key column .
some thing like this
select ID
where
if key = A1 then value ='o1'
and key = A3 then value ='o4'
please help me to write this query.
***To clarify my question ,I need list of IDs in result that all condition(key-value) are true for them. for each IDs I should check key-values (with AND ) and if all conditions are true then this ID is acceptable .
thanks
IF means PL/SQL. In SQL, we use CASE expression instead (or DECODE, if you want). Doing so, you'd move value out of the expression and use something like this:
where id = 1
and value = case when key = 'A1' then 'o1'
when key = 'A3' then 'o4'
end
You are mixing filtering and selection. List the columns that you want to display in the SELECT list and the columns used to filter in the WHERE clause
SELECT key, value
FROM my_table
WHERE ID = 1 AND key IN ('A1', 'A2')
If there is no value column in your table, you can use the DECODE function
SELECT key, DECODE(key, 'A1', 'o1', 'A2', 'o4', key) AS value
FROM my_table
WHERE ID = 1
After the key, you must specify pairs of search and result values. The pairs can be followed by a default value. In this example, since we did not specify a result for 'A3', the result will be the key itself. If no default value was specified, NULL would be returned for missing search values.
update
It seems that I have misunderstood the question (see #mathguy's comment). You can filter the way you want by simply using the Boolean operators AND and OR
SELECT * FROM
FROM my_table
WHERE
ID = 1 AND
(
key = 'A1' AND value ='o1' OR
key = 'A3' AND value ='o4'
)
By using this pattern it is easy to add more constraints of this kind. Note that AND has precedence over OR (like * over +).
I'm creating a new table and carrying over several columns from a previous table. One of the new fields that I need to create is a flag that will have values 0 or 1 and value needs to be determined based on 6 previous fields in the table.
The 6 previous columns have preexisting values of 0 or 1 stored for each one. This new field needs to check whether any of the 6 columns have 1 and if so set the flag to 0. If there is 0 in all 6 fields then set itself to 1.
Hopefully this makes sense. How can I get this done in oracle? I assume a case statement and some sort of forloop?
You can use greatest() function: GREATEST
create table t_new
as
select
case when greatest(c1,c2,c3,c4,c5,c6)=1 -- at least one of them contains 1
then 0
else 1
end c_new
from t_old;
Or even shorter:
create table t_new
as
select
1-greatest(c1,c2,c3,c4,c5,c6) as c_new
from t_old;
In case of greatest = 1, (1-1)=0, otherwise (1-0)=1
You can use a virtual column with a case expression; something like:
flag number generated always as (
case when val_1 + val_2 + val_3 + val_4 + val_5 + val_6 = 0 then 1 else 0 end
) virtual
db<>fiddle
or the same thing with greatest() as #Sayan suggested.
Using a virtual column means the flag will be right for newly-inserted rows, and if any of the other values are updated; you won't have to recalculate or update the flag column manually.
I've assumed the other six columns can't be null and are constrained to only be 0 or 1, as the question suggests. If they can be null you can add nvl() or coalesce() to each term in the calculation.
I have two columns (A and B) on table 1, and I want to concatenate them into another column (C) only if the beginning of B is not A, and if that is not the case, just copy B into C.
The key point here is that A and B do not have a fixed length, so I don't think I can use left(), since it needs a specific length.
For example:
ID A B
1 5 48721
2 98 98555
3 98 136
4 841 8417740313
5 841 133889
In this case, column C should include:
For ID=1: 548721
For ID=2: 98555
For ID=3: 98136
For ID=4: 8417740313
For ID=5: 841133889
I was trying:
UPDATE 1
SET C = B
WHERE LEFT (B) = A
UPDATE 1
SET C = concat(A,B)
WHERE LEFT(B) <> A
But it doesn't work, since I need to give left() a fixed length. What would you guys do?
You seem to want something like this:
UPDATE t
SET C = (CASE WHEN B LIKE A || '%' THEN B ELSE A || B END);
That is, you can use LIKE for the comparison.
Step1:
update table
set col_c = col_a||substr(col_b,length(col_a))
where
substr(col_b,1,length(col_a))=col_a;
Step2:
update table
set col_c = col_a||col_b
where
substr(col_b,1,length(col_a))<>col_a;
you can try this and let us know,
the earlier given solution is also correct; but what if the same eg: 98 in col_a is present in the middle of col_b instead of in the start ?
I have this table
id value
1 OK
2 xminimum
3 NO
4 YES
I want to sort this table by value where minimum is always first then the rest according to alphabetic order of value column
Meaning:
xminimum
NO
OK
YES
I wrote this query:
Select *
from table_a
order by case when value='xminimum' then 1 else ????? end
I don't know what to put in the else... conceptually it should be else value end so it means alphabetic order.. but I can not combine integer with text.
How do I fix it?
As requested, copied from my comment:
Select *
from table_a
order by case when value='xminimum' then 1 else 2 end, value
Another solution:
SELECT *
FROM table_a
ORDER BY value <> 'xminimum', value;
Do it like you have and add the value column as second column to sort by:
SELECT *
FROM table_a
ORDER BY CASE WHEN value='xminimum' THEN 1 ELSE 2 END, value
I want to update table A in such a way that if the attribute of the table column is desired then only it will change otherwise it wont change..
Update table A set B="abcd" ,C= (case when C="abc" then C="abcd" else C end) where column =1;
means C should be only change when in column=1 and C value is abc otherwise C should not be update ..it should be dropped and only B changes. but if the C
value get matched i.e abc give me the output 0 .. not changing to the abcd
Inside the THEN part, C="abcd" compares C with the value, and returns either 1 or 0.
The entire CASE expression should just return a value that then gets written into the C column, so you want just 'abcd' in this place:
UPDATE tableA
SET B = 'abcd',
C = CASE
WHEN C = 'abc' THEN 'abcd'
ELSE C
END
WHERE column = 1;
If I understand you correctly, you're trying to do two separate things:
UPDATE A set B = 'abcd' WHERE column = 1
UPDATE A set C = 'abcd' WHERE C = 'abc' AND column = 1
Is that right? If so, can you do it as two simple statements instead of one complicated statement?