SQL Server SELECT to JSON function

2020-01-24 20:17发布

问题:

I would like to output the results of a SELECT statement as a JSON object.

I would like this to be a Function and not a stored procedure!

For example, the below table Users

id    name        active
1     Bob Jones   1
2     John Smith  0

Would be returned like this:

[{"id":1,"name":"Bob Jones","active":1},{"id":2,"name":"John Smith","active":0}]

Thanks in advance.

回答1:

Starting from SQL Server 2016 you can use for json:

declare @t table(id int, name nvarchar(max), active bit)
insert @t values (1, 'Bob Jones', 1), (2, 'John Smith', 0)

select id, name, active
from @t
for json auto

With older versions of SQL Server you can use for xml path, e.g.:

select '[' + STUFF((
        select 
            ',{"id":' + cast(id as varchar(max))
            + ',"name":"' + name + '"'
            + ',"active":' + cast(active as varchar(max))
            +'}'

        from @t t1
        for xml path(''), type
    ).value('.', 'varchar(max)'), 1, 1, '') + ']'

Output:

[{"id":1,"name":"Bob Jones","active":1},{"id":2,"name":"John Smith","active":0}]


回答2:

Just for improving answer with latest technology change. with sql server 2016

select id, name ,active 
    from  tableName 
      FOR JSON AUTO


回答3:

So first off, I want to thank Kirill Polishchuk for the essential code sample ... thank you!

I took that and went to build a procedure to do what I need it to do, and that is to give me a JSON output based on "any" result set I want i.e. table object (not variable) in SQL Server.

Ideally, I would want this as a function, however due to limitations on what you can do within a function, that part will have to wait ... maybe v2. :)

And yes, registering an extended procedure (CLR) definitely be easier, but I wanted to avoid going that route for the time being.

PS: for temp tables, just put in 'tempdb..#tablename'

Here it is:

            /* 
            Author:         Goran Biljetina
            Create date:    03/13/2013
            Description:    consume a table object (not table var), output it as JSON Properties string
            */

            /*
            --> example run
            -- EXEC dbo.JSONreturn @tblObjNameFQ='[database].[schema].[object_name_table]';
            */

            CREATE PROCEDURE dbo.JSONreturn
            (
            @committedRead bit = 0 --> if 1 then committed else uncommitted read
            ,@debugmode bit = 0    --> if 1 display certain outputs
            ,@tblObjNameFQ varchar(128) --> fully qualified table object name, i.e. db.schema.object_name
            ,@stringJSON nvarchar(max) = null OUTPUT
            )

            AS
            BEGIN

                if @committedRead=0
                begin
                    SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; --> evaluate if necessary in test phase
                end
                    else if @committedRead=1
                        begin
                            SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
                        end

                SET NOCOUNT ON;

                ----------------------------------------------------------------------------------------------------------
                if (PATINDEX('%[\.]%',@tblObjNameFQ)<1 AND patindex('%#%',@tblObjNameFQ)<1) OR LEN(@tblObjNameFQ)>(3*128)
                begin
                    PRINT 'table (object) name not fully qualified or invalid!'
                    RETURN -1
                end


                declare 
                @objname varchar(128)
                ,@dbname varchar(128)
                ,@schema varchar(128)
                ,@maxColNum int
                ,@inc int
                ,@dqsl_misc varchar(max)
                ,@dsql_wrapper varchar(max)
                ,@dsql_what varchar(max)
                ,@dsql_where varchar(max)
                ,@dsql_complete varchar(max)


                create table #maxColNum (column_id int)
                create table #ColPrep (colString varchar(max), column_id int)
                create table #JSONoutput (string nvarchar(max))


                if patindex('%#%',@tblObjNameFQ)>0
                begin
                    set @objname = (PARSENAME(@tblObjNameFQ,1))
                    set @dbname = 'tempdb'
                end
                else if patindex('%#%',@tblObjNameFQ)<1
                    begin
                        set @dbname = SUBSTRING(@tblObjNameFQ,1,PATINDEX('%[\.]%',@tblObjNameFQ)-1)
                        set @objname = convert(varchar,(PARSENAME(@tblObjNameFQ,1)))
                        set @schema = convert(varchar,(PARSENAME(@tblObjNameFQ,2)))
                    end

                --select @objname[@objname], @dbname[@dbname], @schema[@schema]
                --select @dbname+'.'+@schema+'.'+@objname

                set @dqsl_misc =
                '
                select max(column_id) 
                from '+@dbname+'.sys.columns 
                where object_id = 
                (select object_id from '+@dbname+'.sys.objects where type = ''U'' and name like ''%'+@objname+'%'')
                '
                insert into #maxColNum
                exec(@dqsl_misc)

                set @maxColNum = (select column_id from #maxColNum)
                set @dsql_what = ''

                set @dsql_wrapper = 
                '
                select ''['' + STUFF((
                        select 
                            '',{''+<<REPLACE>>
                            +''}''
                '
                set @dsql_where =
                '
                        from '+@dbname+'.'+case when @schema is null then '' else @schema end+'.'+@objname+' t1
                        for xml path(''''), type
                    ).value(''.'', ''varchar(max)''), 1, 1, '''') + '']''
                '

                set @dqsl_misc =
                '
                select ''"''+sysc.name+''": '' 
                        +case 
                        when syst.name like ''%time%'' or syst.collationid is not null then ''"''''+cast(''+sysc.name+'' as varchar(max))+''''",''
                        when syst.name = ''bit'' then ''''''+cast((case when ''+sysc.name+''=1 then ''''true'''' else ''''false'''' end) as varchar(max))+'''',''
                        else ''''''+cast(''+sysc.name+'' as varchar(max))+'''',''
                        end as colString, sysc.column_id
                from '+@dbname+'.sys.columns sysc
                    join '+@dbname+'.sys.systypes syst
                        on sysc.system_type_id = syst.xtype and syst.xtype <> 240 and syst.name <> ''sysname''
                where object_id = (select object_id from '+@dbname+'.sys.objects where type = ''U'' and name like ''%'+@objname+'%'')
                order by sysc.column_id
                '
                insert into #ColPrep
                exec(@dqsl_misc)

                set @inc = (select MIN(column_id) from #ColPrep)


                while @inc<=@maxColNum
                begin

                    set @dsql_what = @dsql_what+(select case 
                                                when @inc = @maxColNum then replace(colString,',','') 
                                                else colString end 
                                                from #ColPrep where column_id = @inc)

                    set @inc=@inc+1

                    IF @inc>@maxColNum
                        set @dsql_what = ''''+@dsql_what+''''

                    IF @inc>@maxColNum
                        BREAK
                    ELSE
                        CONTINUE
                end

                set @dsql_complete = REPLACE(@dsql_wrapper,'<<REPLACE>>',@dsql_what)+@dsql_where

                insert into #JSONoutput
                exec(@dsql_complete)

                SET @stringJSON = (Select string from #JSONoutput)
                ----------------------------------------------------------------------------------------------------------

            END