Given a result set which is in the EAV structure such as :
id | attributeName | stringValue | intValue | BooleanValue
---------------------------------------------------------------
1 stringFoo v1
1 stringFooList v2
1 stringFooList v3
1 intFoo 10
1 intFooList 10
1 intFooList 20
1 booleanFoo true
1 booleanFooList true
1 booleanFooList true
How can I select all the attributes and value pair as a single value in a JSON/JSONB format , which are something likes:
{
"stringFoo" : "v1" ,
"stringFooList" : ["v2","v3"] ,
"intFoo" : 10 ,
"intFooList" : [10,20],
"booleanFoo" : true,
"booleanFooList" : [true,true]
}
If there are multiple attribute value for an attribute such as stringFooList , it will format it as JSON array.
I am using PostgreSQL 9.6
You can do something like this:
select id, jsonb_object_agg(att, value)
from (
select id,
attributename as att,
case
when count(*) > 1 then
jsonb_agg(coalesce(stringvalue,intvalue::text,booleanvalue::text))
else
to_jsonb(min(coalesce(stringvalue,intvalue::text,booleanvalue::text)))
end as value
from eav
group by id, attributename
) t
group by id;
The inner select aggregates multiple values into an JSON array, single values into JSON scalar values. And the outer query then builds a single JSON value of all rows.
Online example: https://rextester.com/TLCRN79815
#a_horse_with_no_name 's answer gives me a good start. I extend his/her answer and come up the following query such that the elements in the JSON array have the same data type of what defined in PostgreSQL.
select id, jsonb_object_agg(att,
case
when strval is not null then strval
when intvalue is not null then intvalue
else boolVal
end
)
from (
select id,
attributename as att,
case when count(*) > 1 then
jsonb_agg(stringvalue) filter (where stringvalue is not null)
else
to_jsonb(min(stringvalue) filter (where stringvalue is not null))
end as strVal,
case when count(*) > 1 then
jsonb_agg(intvalue) filter (where intvalue is not null)
else
to_jsonb(min(intvalue) filter (where intvalue is not null))
end as intvalue,
case when count(*) > 1 then
jsonb_agg(booleanvalue) filter (where booleanvalue is not null)
else
to_jsonb(bool_and(booleanvalue) filter (where booleanvalue is not null))
end as boolVal
from eav
group by id, attributename
) t
group by id;
How to return a boolean true/false instead of t/f from a field of string type in Postgres.
SELECT (CASE WHEN status = 'active' THEN true ELSE false END)::boolean AS status
FROM table;
t and f is just how psql prints booleans, it shouldn't be important. Also, you can simplify your query as follows:
SELECT status = 'active' AS status FROM table;
If you really want to get text for the column status, do the following:
SELECT (status = 'active')::text AS status FROM table;
If you want to get a number instead (0 for false, 1 for true), do this:
SELECT (status = 'active')::integer AS status FROM table;
I'm currently using following mapping:
#Select ("select count(*) from something where id = 2344")
int userExists();
But i would like to have something like:
#Select ("select count(*) from something where id = 2344")
boolean userExists();
Can I convert 0 to false and everything > 0 to true ?
I'm using Oracle. Therefore I hope that my-batis provides some sort of return type mapping.
Here is how you can return boolean in Oracle, by using the case statement in Oracle:
#Select ("select case when count(*) > 0 then 1 else 0 end result from something where id = 2344")
boolean userExists();
Hope it is helpful to you.
could you please help?
SELECT
(some columns),
SortOrder = CASE WHEN City = #inParamCity THEN 0 ELSE 1 END
FROM
dbo.addressBook
ORDER BY
SortOrder
I tried this and got:
Incorrect syntax near '=' ' –
SELECT
(some columns)
FROM
dbo.addressBook
ORDER BY
CASE
WHEN City = #inParamCity THEN 0
ELSE 1
END
Shouldn't it be like this?
SELECT (some columns),
CASE City WHEN #inParamCity THEN 0 ELSE 1 END As SortOrder
FROM dbo.addressBook
ORDER BY SortOrder
OK, the umpteenth conditional column question:
I'm writing a stored proc that takes an input parameter that's mapped to one of several flag columns. What's the best way to filter on the requested column? I'm currently on SQL2000, but about to move to SQL2008, so I'll take a contemporary solution if one's available.
The table queried in the sproc looks like
ID ... fooFlag barFlag bazFlag quuxFlag
-- ------- ------- ------- --------
01 1 0 0 1
02 0 1 0 0
03 0 0 1 1
04 1 0 0 0
and I want to do something like
select ID, name, description, ...
from myTable
where (colname like #flag + 'Flag') = 1
so if I call the sproc like exec uspMyProc #flag = 'foo' I'd get back rows 1 and 4.
I know I can't do the part in parens directly in SQL. In order to do dynamic SQL, I'll have to stuff the entire query into a string, concatenate the #flag param in the WHERE clause and then exec the string. Aside from the dirty feeling I get when doing dynamic SQL, my query is fairly large (I'm selecting a couple dozen fields, joining 5 tables, calling a couple of functions), so it's a big giant string all because of a single line in a 3-line WHERE filter.
Alternately, I could have 4 copies of the query and select among them in a CASE statement. This leaves the SQL code directly executable (and subject to syntax hilighting, etc.) but at the cost of repeating big chunks of code, since I can't use the CASE on just the WHERE clause.
Are there any other options? Any tricky joins or logical operations that can be applied? Or should I just get over it and exec the dynamic SQL?
There are a few ways to do this:
You can do this with a case statement.
select ID, name, description, ...
from myTable
where CASE
WHEN #flag = 'foo' then fooFlag
WHEN #flag = 'bar' then barFlag
END = 1
You can use IF.
IF (#flag = 'foo') BEGIN
select ID, name, description, ...
from myTable
where fooFlag = 1
END ELSE IF (#flag = 'bar') BEGIN
select ID, name, description, ...
from myTable
where barFlag = 1
END
....
You can have a complicated where clause with a lot of parentheses.
select ID, name, description, ...
from myTable
where (#flag = 'foo' and fooFlag = 1)
OR (#flag = 'bar' and barFlag = 1) OR ...
You can do this with dynamic sql:
DECLARE #SQL nvarchar(4000)
SELECT #SQL = N'select ID, name, description, ...
from myTable
where (colname like ''' + #flag + 'Flag'') = 1'
EXECUTE sp_ExecuteSQL #SQL, N''
There are more, but I think one of these will get you going.
"Alternately, I could have 4 copies of the query and select among them in a CASE statement."
You don't need to copy your entire query 4 times, just add all the possibilities into the where clauses in your single copy of the query:
select ID, name, description, ...
from myTable
where (#flag = 'foo' and fooFlag = 1) OR (#flag = 'bar' and barFlag = 1) OR ...
What I would do is CASE some variables at the beginning. Example:
DECLARE
#fooFlag int,
#barFlag int,
#bazFlag int,
#quuxFlag int
SET #fooFlag = CASE WHEN #flag = 'foo' THEN 1 ELSE NULL END
SET #barFlag = CASE WHEN #flag = 'bar' THEN 1 ELSE NULL END
SET #bazFlag = CASE WHEN #flag = 'baz' THEN 1 ELSE NULL END
SET #quuxFlag = CASE WHEN #flag = 'quux' THEN 1 ELSE NULL END
SELECT ID, name, description, ...
FROM myTable
WHERE (fooFlag >= ISNULL(#fooFlag, 0) AND fooFlag <= ISNULL(#fooFlag, 1))
AND (barFlag >= ISNULL(#barFlag, 0) AND barFlag <= ISNULL(#barFlag, 1))
AND (bazFlag >= ISNULL(#bazFlag, 0) AND bazFlag <= ISNULL(#bazFlag, 1))
AND (quuxFlag >= ISNULL(#quuxFlag, 0) AND quuxFlag <= ISNULL(#quuxFlag, 1))
The good thing about this query is that, because the possible values for "flags" are bounded, you can calculate all your conditionals as prerequisites instead of wrapping columns in them. This guarantees a high-performance index seek on whichever columns are indexed, and doesn't require writing any dynamic SQL. And it's better than writing 4 separate queries for obvious reasons.
You could have a parameter for each possible flag column, then check if the parameter is null or the value in the column is equal to the parameter. Then you pass in a 1 for the flags that you want to check and leave the others null.
select id, name, description, ...
from myTable
where (#fooFlag is null or fooFlag = #fooFlag) AND
(#barFlag is null or barFlag = #barFlag) AND
...
Honestly, though, this seems like an ideal candidate for building a dynamic LINQ query and skipping the SPROC once you get to SQL2008.
int should be accepted as varchar value
declare #CompanyID as varchar(10) = '' -- or anyother value
select * from EmployeeChatTbl chat
where chat.ConversationDetails like '%'+#searchKey+'%'
and
(
(0 = CASE WHEN (#CompanyID = '' ) THEN 0 ELSE 1 END)
or
(chat.CompanyID = #CompanyID)
)
working
when the companyID is present , then filtration based on it is done, other wise , filtration is skipped.
where
case when #value<>0 then Field else 1 end
=
case when #value<>0 then #value else 1 end