Postgres 10.5: Create Materialized View where column data may be empty/null?
I am creating a Materialized View from two tables, using the array_agg function to join strings from table_b to table_a. Essentially, column_c on table_a is a nullable array of numbers corresponding to the id column of table_b (which has only two columns, id and description). However, the Materialized View fails to include a row for any row on table_a that is null / empty on column_c.
Is it possible to make the Materialized either (1) enter an empty array; or (2) a null value, when table_a column_c value is null?
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
FROM table_a
JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
postgresql materialized-views
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
add a comment |
I am creating a Materialized View from two tables, using the array_agg function to join strings from table_b to table_a. Essentially, column_c on table_a is a nullable array of numbers corresponding to the id column of table_b (which has only two columns, id and description). However, the Materialized View fails to include a row for any row on table_a that is null / empty on column_c.
Is it possible to make the Materialized either (1) enter an empty array; or (2) a null value, when table_a column_c value is null?
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
FROM table_a
JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
postgresql materialized-views
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
add a comment |
I am creating a Materialized View from two tables, using the array_agg function to join strings from table_b to table_a. Essentially, column_c on table_a is a nullable array of numbers corresponding to the id column of table_b (which has only two columns, id and description). However, the Materialized View fails to include a row for any row on table_a that is null / empty on column_c.
Is it possible to make the Materialized either (1) enter an empty array; or (2) a null value, when table_a column_c value is null?
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
FROM table_a
JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
postgresql materialized-views
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
I am creating a Materialized View from two tables, using the array_agg function to join strings from table_b to table_a. Essentially, column_c on table_a is a nullable array of numbers corresponding to the id column of table_b (which has only two columns, id and description). However, the Materialized View fails to include a row for any row on table_a that is null / empty on column_c.
Is it possible to make the Materialized either (1) enter an empty array; or (2) a null value, when table_a column_c value is null?
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
FROM table_a
JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
postgresql materialized-views
postgresql materialized-views
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
asked Dec 31 '18 at 20:48
KwhitejrKwhitejr
4061518
4061518
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Use LEFT JOIN:
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
-- or
-- coalesce(array_agg(description), '{}') as column_c
FROM table_a
LEFT JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53991304%2fpostgres-10-5-create-materialized-view-where-column-data-may-be-empty-null%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Use LEFT JOIN:
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
-- or
-- coalesce(array_agg(description), '{}') as column_c
FROM table_a
LEFT JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
add a comment |
Use LEFT JOIN:
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
-- or
-- coalesce(array_agg(description), '{}') as column_c
FROM table_a
LEFT JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
add a comment |
Use LEFT JOIN:
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
-- or
-- coalesce(array_agg(description), '{}') as column_c
FROM table_a
LEFT JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
Use LEFT JOIN:
CREATE MATERIALIZED VIEW my_materialized_view
AS
SELECT
id,
column_a,
column_b,
array_agg(description) as column_c
-- or
-- coalesce(array_agg(description), '{}') as column_c
FROM table_a
LEFT JOIN table_b on table_b.id = any(column_c)
GROUP BY table_a.id
ORDER BY table_a.id ASC
WITH DATA;
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
answered Dec 31 '18 at 21:57
klinklin
58.8k65283
58.8k65283
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
add a comment |
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
For others like myself who need a refresher in JOIN types: sql-join.com/sql-join-types
– Kwhitejr
Jan 1 at 1:08
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53991304%2fpostgres-10-5-create-materialized-view-where-column-data-may-be-empty-null%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
