How can I initialise an apex Set, Set or Set from SOQL in Apex Code?

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up vote
2
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Is this possible? I would like to do the following directly:

Set<String> titles = new Set<String>([Select Title From SObject]);

asked Sep 5 at 14:08

KennyBartMan

1807

3

this functionality doesn't exist unfortunately. You will have to iterate over the list of SObjects and manually add the title fields to the set.
â€“Â Programatic
Sep 5 at 14:15

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up vote
2
down vote

favorite

Is this possible? I would like to do the following directly:

Set<String> titles = new Set<String>([Select Title From SObject]);

asked Sep 5 at 14:08

KennyBartMan

1807

3

this functionality doesn't exist unfortunately. You will have to iterate over the list of SObjects and manually add the title fields to the set.
â€“Â Programatic
Sep 5 at 14:15

add a commentÂ |Â

up vote
2
down vote

favorite

Is this possible? I would like to do the following directly:

Set<String> titles = new Set<String>([Select Title From SObject]);

asked Sep 5 at 14:08

KennyBartMan

1807

Is this possible? I would like to do the following directly:

Set<String> titles = new Set<String>([Select Title From SObject]);

asked Sep 5 at 14:08

KennyBartMan

1807

asked Sep 5 at 14:08

KennyBartMan

1807

asked Sep 5 at 14:08

KennyBartMan

1807

asked Sep 5 at 14:08

KennyBartMan

1807

3

this functionality doesn't exist unfortunately. You will have to iterate over the list of SObjects and manually add the title fields to the set.
â€“Â Programatic
Sep 5 at 14:15

add a commentÂ |Â

3

this functionality doesn't exist unfortunately. You will have to iterate over the list of SObjects and manually add the title fields to the set.
â€“Â Programatic
Sep 5 at 14:15

this functionality doesn't exist unfortunately. You will have to iterate over the list of SObjects and manually add the title fields to the set.
â€“Â Programatic
Sep 5 at 14:15

add a commentÂ |Â

2 Answers
2

active

oldest

votes

up vote
7
down vote

accepted

No it is not possible except for Set<Id>. With other types, you need a for loop:

Set<String> names = new Set<String>();
for (MyObject__c record : [SELECT Name FROM MyObject__c])
 names.add(record.Name);

The special case is that with a record's own Id, you can use this Map constructor:

Set<Id> ids = new Map<Id, SObject>([/*query*/]).keySet();

You can abuse this shortcut and field alias functionality in aggregate queries to get a collection of parent Ids also.

Set<Id> parentIds = new Map<Id, SObject>([
 SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c
// ^^ you can now call .get('Id') on a result record
]).keySet();

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

1

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

2

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Â |Â
show 1 more comment

up vote
3
down vote

You can do it fairly easily for the Set of Id use case by passing the SOQL to the constructor of an Id to Sobject Map and then grabbing the keyset from this;-

Set<Id> Ids = new Map<Id, Sobject>([SELECT Id FROM SObject]).keySet();

Other than that though there isn't a direct way to do it for non-Id fields. Your best bet would probably to create a reusable worker method to handle this.

Depending on what you need this for aggregate SOQL functions may help as they will produce a list of all unique values for the aggregated field.

Set<String> titles = new Set<String>();
for(AggregateResult ar : [SELECT Title FROM SObject GROUP BY Title])
 titles.add((String)ar.get('Title'));

answered Sep 5 at 14:41

Alex 255

312

New contributor

add a commentÂ |Â

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
7
down vote

accepted

No it is not possible except for Set<Id>. With other types, you need a for loop:

Set<String> names = new Set<String>();
for (MyObject__c record : [SELECT Name FROM MyObject__c])
 names.add(record.Name);

The special case is that with a record's own Id, you can use this Map constructor:

Set<Id> ids = new Map<Id, SObject>([/*query*/]).keySet();

You can abuse this shortcut and field alias functionality in aggregate queries to get a collection of parent Ids also.

Set<Id> parentIds = new Map<Id, SObject>([
 SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c
// ^^ you can now call .get('Id') on a result record
]).keySet();

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

1

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

2

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Â |Â
show 1 more comment

up vote
7
down vote

accepted

No it is not possible except for Set<Id>. With other types, you need a for loop:

Set<String> names = new Set<String>();
for (MyObject__c record : [SELECT Name FROM MyObject__c])
 names.add(record.Name);

The special case is that with a record's own Id, you can use this Map constructor:

Set<Id> ids = new Map<Id, SObject>([/*query*/]).keySet();

You can abuse this shortcut and field alias functionality in aggregate queries to get a collection of parent Ids also.

Set<Id> parentIds = new Map<Id, SObject>([
 SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c
// ^^ you can now call .get('Id') on a result record
]).keySet();

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

1

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

2

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Â |Â
show 1 more comment

up vote
7
down vote

accepted

No it is not possible except for Set<Id>. With other types, you need a for loop:

Set<String> names = new Set<String>();
for (MyObject__c record : [SELECT Name FROM MyObject__c])
 names.add(record.Name);

The special case is that with a record's own Id, you can use this Map constructor:

Set<Id> ids = new Map<Id, SObject>([/*query*/]).keySet();

You can abuse this shortcut and field alias functionality in aggregate queries to get a collection of parent Ids also.

Set<Id> parentIds = new Map<Id, SObject>([
 SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c
// ^^ you can now call .get('Id') on a result record
]).keySet();

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

No it is not possible except for Set<Id>. With other types, you need a for loop:

Set<String> names = new Set<String>();
for (MyObject__c record : [SELECT Name FROM MyObject__c])
 names.add(record.Name);

The special case is that with a record's own Id, you can use this Map constructor:

Set<Id> ids = new Map<Id, SObject>([/*query*/]).keySet();

You can abuse this shortcut and field alias functionality in aggregate queries to get a collection of parent Ids also.

Set<Id> parentIds = new Map<Id, SObject>([
 SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c
// ^^ you can now call .get('Id') on a result record
]).keySet();

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

edited Sep 5 at 17:22

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

answered Sep 5 at 14:42

Adrian Larsonâ™¦

100k19106224

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

1

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

2

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Â |Â
show 1 more comment

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

1

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

2

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Missing comma between Parent__c and Id in the SOQL query.
â€“Â Tad
Sep 5 at 17:15

No. That is the whole point of including that query. What it was actually missing is the GROUP BY clause.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:17

I don't understand. You're saying you intentionally left out the comma between Parent__c and Id in your example. This query as is won't work without a comma between the fields. SELECT Parent__c Id FROM MyObject__c GROUP BY Parent__c Adding a comma will make it work. SELECT Parent__c, Id FROM MyObject__c GROUP BY Parent__c If I'm not following then it might be that your explanation needs a bit more clarification as to why you left it out.
â€“Â Tad
Sep 5 at 17:20

I didn't leave anything out. I am not showing how to query two separate fields. I am using alias functionally.
â€“Â Adrian Larsonâ™¦
Sep 5 at 17:21

Ahhhh... I see now. My fault. Interesting solution.
â€“Â Tad
Sep 5 at 17:22

Â |Â
show 1 more comment

up vote
3
down vote

You can do it fairly easily for the Set of Id use case by passing the SOQL to the constructor of an Id to Sobject Map and then grabbing the keyset from this;-

Set<Id> Ids = new Map<Id, Sobject>([SELECT Id FROM SObject]).keySet();

Other than that though there isn't a direct way to do it for non-Id fields. Your best bet would probably to create a reusable worker method to handle this.

Depending on what you need this for aggregate SOQL functions may help as they will produce a list of all unique values for the aggregated field.

Set<String> titles = new Set<String>();
for(AggregateResult ar : [SELECT Title FROM SObject GROUP BY Title])
 titles.add((String)ar.get('Title'));

answered Sep 5 at 14:41

Alex 255

312

New contributor

add a commentÂ |Â

up vote
3
down vote

You can do it fairly easily for the Set of Id use case by passing the SOQL to the constructor of an Id to Sobject Map and then grabbing the keyset from this;-

Set<Id> Ids = new Map<Id, Sobject>([SELECT Id FROM SObject]).keySet();

Other than that though there isn't a direct way to do it for non-Id fields. Your best bet would probably to create a reusable worker method to handle this.

Depending on what you need this for aggregate SOQL functions may help as they will produce a list of all unique values for the aggregated field.

Set<String> titles = new Set<String>();
for(AggregateResult ar : [SELECT Title FROM SObject GROUP BY Title])
 titles.add((String)ar.get('Title'));

answered Sep 5 at 14:41

Alex 255

312

New contributor

add a commentÂ |Â

up vote
3
down vote

You can do it fairly easily for the Set of Id use case by passing the SOQL to the constructor of an Id to Sobject Map and then grabbing the keyset from this;-

Set<Id> Ids = new Map<Id, Sobject>([SELECT Id FROM SObject]).keySet();

Other than that though there isn't a direct way to do it for non-Id fields. Your best bet would probably to create a reusable worker method to handle this.

Depending on what you need this for aggregate SOQL functions may help as they will produce a list of all unique values for the aggregated field.

Set<String> titles = new Set<String>();
for(AggregateResult ar : [SELECT Title FROM SObject GROUP BY Title])
 titles.add((String)ar.get('Title'));

answered Sep 5 at 14:41

Alex 255

312

New contributor

You can do it fairly easily for the Set of Id use case by passing the SOQL to the constructor of an Id to Sobject Map and then grabbing the keyset from this;-

Set<Id> Ids = new Map<Id, Sobject>([SELECT Id FROM SObject]).keySet();

Other than that though there isn't a direct way to do it for non-Id fields. Your best bet would probably to create a reusable worker method to handle this.

Depending on what you need this for aggregate SOQL functions may help as they will produce a list of all unique values for the aggregated field.

Set<String> titles = new Set<String>();
for(AggregateResult ar : [SELECT Title FROM SObject GROUP BY Title])
 titles.add((String)ar.get('Title'));

answered Sep 5 at 14:41

Alex 255

312

New contributor

answered Sep 5 at 14:41

Alex 255

312

New contributor

answered Sep 5 at 14:41

Alex 255

312

answered Sep 5 at 14:41

Alex 255

312

New contributor

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