I'm trying to update a row in my PostgreSQL database and it's saying it's not finding the x column. the thing is the column pg is trying to find is actually a parameter for the new value in the jsonb_set function, so I'm at my wits end.
It's hard to explain, so I included the query and the error it throws.
Tried adding quotes, double-quotes, brackets, inside and out... didn't work.
UPDATE public.sometable
SET somecolumn = jsonb_set(somecolumn, '{firstKey, secondKey}', someInputString), update_date=NOW(), update_username="someone#somewhere.com"
WHERE id=1
RETURNING *
I'm expecting the value of the row I'm updating to be returned, instead I get:
ERROR: column "someInputString" does not exist
LINE 1: ...n = jsonb_set(somecolumn , '{firstKey, secondKey}', someInputString)...
You have to deliver a valid json value as the third argument of the function:
UPDATE public.sometable
SET
somecolumn = jsonb_set(somecolumn, '{firstKey, secondKey}', '"someInputString"'),
update_date = now(),
update_username = 'someone#somewhere.com'
WHERE id = 1
RETURNING *
Note, I guess update_username is a text, so you should use single quotes for a simple text.
Db<>fiddle.
Related
I am using Postgresql. My Yii2 code for the update is
ModelName::updateAll(['my_column' => "REPLACE(my_column1,'removed_','')"]);
Actual query is
update my_table set my_column = REPLACE(my_column1,'removed_','');
When I run my yii2 code it shows the error
SQLSTATE[22001]: String data, right truncated: 7 ERROR: value too long for type character varying(50)
The SQL being executed was: UPDATE "my_table" SET "my_column1"='REPLACE(my_column1,''removed_'','''')'
If you use ['column' => 'value'] syntax for attributes the framework expects that values of array are simple values and treats them accordingly. That's why your expression gets converted to string value instead of using as expression.
If you want to avoid that you need to wrap your values in yii\db\Expression like this:
ModelName::updateAll([
'my_column' => new \yii\db\Expression("REPLACE(my_column1,'removed_','')")
]);
original query looks like this :
UPDATE reponse_question_finale t1, reponse_question_finale t2 SET
t1.nb_question_repondu = (9-(ISNULL(t1.valeur_question_4)+ISNULL(t1.valeur_question_6)+ISNULL(t1.valeur_question_7)+ISNULL(t1.valeur_question_9))) WHERE t1.APPLICATION = t2.APPLICATION;
I know you cannot update 2 tables in a single query so i tried this :
UPDATE reponse_question_finale t1
SET nb_question_repondu = (9-(COALESCE(t1.valeur_question_4,'')::int+COALESCE(t1.valeur_question_6,'')::int+COALESCE(t1.valeur_question_7)::int+COALESCE(t1.valeur_question_9,'')::int))
WHERE t1.APPLICATION = t1.APPLICATION;
But this query gaves me an error : invalid input syntax for integer: ""
I saw that the Postgres equivalent to MySQL is COALESCE() so i think i'm on the good way here.
I also know you cannot add varchar to varchar so i tried to cast it to integer to do that. I'm not sure if i casted it correctly with parenthesis at the good place and regarding to error maybe i cannot cast to int with coalesce.
Last thing, i can certainly do a co-related sub-select to update my two tables but i'm a little lost at this point.
The output must be an integer matching the number of questions answered to a backup survey.
Any thoughts?
Thanks.
coalesce() returns the first non-null value from the list supplied. So, if the column value is null the expression COALESCE(t1.valeur_question_4,'') returns an empty string and that's why you get the error.
But it seems you want something completely different: you want check if the column is null (or empty) and then subtract a value if it is to count the number of non-null columns.
To return 1 if a value is not null or 0 if it isn't you can use:
(nullif(valeur_question_4, '') is null)::int
nullif returns null if the first value equals the second. The IS NULL condition returns a boolean (something that MySQL doesn't have) and that can be cast to an integer (where false will be cast to 0 and true to 1)
So the whole expression should be:
nb_question_repondu = 9 - (
(nullif(t1.valeur_question_4,'') is null)::int
+ (nullif(t1.valeur_question_6,'') is null)::int
+ (nullif(t1.valeur_question_7,'') is null)::int
+ (nullif(t1.valeur_question_9,'') is null)::int
)
Another option is to unpivot the columns and do a select on them in a sub-select:
update reponse_question_finale
set nb_question_repondu = (select count(*)
from (
values
(valeur_question_4),
(valeur_question_6),
(valeur_question_7),
(valeur_question_9)
) as t(q)
where nullif(trim(q),'') is not null);
Adding more columns to be considered is quite easy then, as you just need to add a single line to the values() clause
This question already has an answer here:
How to handle an optional value returned by a query using the postgres crate?
(1 answer)
Closed 5 years ago.
I am using the rust-postgres library and I want to do a SELECT and check if the first column of the first row is NULL or not.
This is how I get my data:
let result = connection.query(
r#"
SELECT structure::TEXT
FROM sentence
WHERE id = $1
"#,
&[&uuid]
);
let rows = result.expect("problem while getting sentence");
let row = rows
.iter()
.next() // there's only 1 result
.expect("0 results, expected one...");
The only simple way I found to figure it out is the following code:
match row.get_opt(0) {
Some(Ok(data)) => some data found,
Some(Err(_)) => the column is null,
None => out of bound column index
}
Unfortunately, it seems that Some(Err(_)) is the executed path for any kind of SQL/database error, and not only if the retrieved column is NULL.
Which condition should I use to check that the column is NULL ?
If all you need to know is whether the column is NULL, you could try changing your query to:
SELECT COUNT(1) FROM sentence WHERE id = $1 AND structure IS NOT NULL
with or without the NOT.
If you want to make the logic simpler so any error is an actual error, I'd consider changing the select value to something like:
COALESCE( structure::TEXT, ''::TEXT ) AS "structure"
so it should never be NULL. That should work as long as an empty string isn't a valid non-NULL value for that column.
Otherwise, I may have misunderstood your problem.
I have the following code in Postgres
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where op.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
which returns 1 row.
Then I try to update the url field with the following:
update identity.profile
set url = 'htpp:sam'
where identity.profile.url in (
select op.url from identity.legal_entity le
join identity.profile op on le.legal_entity_id =op.legal_entity_id
where global_id = '8wyvr9wkd7kpg1n0q4klhkc4g'
);
But the above ends up updating more than 1 row, actually all of the rows of the identity table.
I would assume since the first postgres statement returns one row, only one row at most can be updated, but I am getting the wrong effect where all of the rows are being updated. Why ?? Please help a nubie fix the above update statement.
Instead of using profile.url to identify the row you want to update, use the primary key. That is what it is there for.
So if the primary key column is called id, the statement could be modified to:
UPDATE identity.profile
SET ...
WHERE identity.profile.id IN (SELECT op.id FROM ...);
But you can do this much simpler in PostgreSQL with
UPDATE identity.profile op
SET url = 'htpp:sam'
FROM identity.legal_entity le
WHERE le.legal_entity_id = op.legal_entity_id
AND le.global_id = '8wyvr9wkd7kpg1n0q4klhkc4g';
I have the problem with the following CTE expression because prev_count in new_values is being interpreted as text, but the column I'm updating in counts is type integer. I'm getting this error on the marked line:
ERROR: column "prev_count" is of type integer but expression is of type text
LINE 12: prev_count = new_values.prev_count
Here's the query:
WITH
new_values (word,count,txid,prev_count) AS (
VALUES ('cat',1,5,NULL)),
updated AS (
UPDATE
counts t
SET
count = new_values.count,
txid = new_values.txid,
prev_count = new_values.prev_count -- ERROR HERE
FROM
new_values
WHERE (
t.word = new_values.word
)
RETURNING t.*)
INSERT INTO counts(
word,count,txid,prev_count
) SELECT
word,count,txid,prev_count FROM new_values
WHERE NOT EXISTS (
SELECT 1 FROM updated WHERE (updated.word = new_values.word))
My question is, what's an elegant way to fix the error? I would rather specify the type of prev_count in new_values instead of adding an explicit cast, but I don't see anything like that in the docs.
Adding this here as an explicit answer along with a detailed explanation.
The fix is:
WITH
new_values (word,count,txid,prev_count) AS (
VALUES ('cat',1,5,NULL::text)),
As a_horse_with_no_name suggested in the comments.
Why is this necessary? Because the row specification comes from the VALUES section and NULL is unknown. In this case PostgreSQL helpfully casts to text. But that is not what you want so you have to give a type to the NULL.
This often comes up in other cases too, such as UNION statements where a NULL in the first segment in the column list can be given an implicit type which clashes with the type of the column in another segment. So this is a tricky corner worth knowing about.