转 国外大牛写的一个通用行转列 oralce专用

Posted 2020-09-12

CREATE OR REPLACE
type PivotImpl as object
(
ret_type anytype, -- The return type of the table function
stmt varchar2(32767),
fmt varchar2(32767),
cur integer,
static function ODCITableDescribe( rtype out anytype, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number := 0 )
return number,
static function ODCITablePrepare( sctx out PivotImpl, ti in sys.ODCITabFuncInfo, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number := 0 )
return number,
static function ODCITableStart( sctx in out PivotImpl, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number := 0 )
return number,
member function ODCITableFetch( self in out PivotImpl, nrows in number, outset out anydataset )
return number,
member function ODCITableClose( self in PivotImpl )
return number
)
/

create or replace type body PivotImpl as
static function ODCITableDescribe( rtype out anytype, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number )
return number
is
atyp anytype;
cur integer;
numcols number;
desc_tab dbms_sql.desc_tab2;
rc sys_refcursor;
t_c2 varchar2(32767);
t_fmt varchar2(1000);
begin
cur := dbms_sql.open_cursor;
dbms_sql.parse( cur, p_stmt, dbms_sql.native );
dbms_sql.describe_columns2( cur, numcols, desc_tab );
dbms_sql.close_cursor( cur );
--
anytype.begincreate( dbms_types.typecode_object, atyp );
for i in 1 .. numcols - 2
loop
atyp.addattr( desc_tab( i ).col_name
, case desc_tab( i ).col_type
when 1 then dbms_types.typecode_varchar2
when 2 then dbms_types.typecode_number
when 9 then dbms_types.typecode_varchar2
when 11 then dbms_types.typecode_varchar2 -- show rowid as varchar2
when 12 then dbms_types.typecode_date
when 208 then dbms_types.typecode_varchar2 -- show urowid as varchar2
when 96 then dbms_types.typecode_char
when 180 then dbms_types.typecode_timestamp
when 181 then dbms_types.typecode_timestamp_tz
when 231 then dbms_types.typecode_timestamp_ltz
when 182 then dbms_types.typecode_interval_ym
when 183 then dbms_types.typecode_interval_ds
end
, desc_tab( i ).col_precision
, desc_tab( i ).col_scale
, case desc_tab( i ).col_type
when 11 then 18 -- for rowid col_max_len = 16, and 18 characters are shown
else desc_tab( i ).col_max_len
end
, desc_tab( i ).col_charsetid
, desc_tab( i ).col_charsetform
);
end loop;
if instr( p_fmt, ‘@[email protected]‘ ) > 0
then
t_fmt := p_fmt;
else
t_fmt := ‘@[email protected]‘;
end if;
open rc for replace( ‘select distinct ‘ || t_fmt || ‘
from( ‘ || p_stmt || ‘ )
order by ‘ || t_fmt
, ‘@[email protected]‘
, desc_tab( numcols - 1 ).col_name
);
loop
fetch rc into t_c2;
exit when rc%notfound;
atyp.addattr( t_c2
, case desc_tab( numcols ).col_type
when 1 then dbms_types.typecode_varchar2
when 2 then dbms_types.typecode_number
when 9 then dbms_types.typecode_varchar2
when 11 then dbms_types.typecode_varchar2 -- show rowid as varchar2
when 12 then dbms_types.typecode_date
when 208 then dbms_types.typecode_urowid
when 96 then dbms_types.typecode_char
when 180 then dbms_types.typecode_timestamp
when 181 then dbms_types.typecode_timestamp_tz
when 231 then dbms_types.typecode_timestamp_ltz
when 182 then dbms_types.typecode_interval_ym
when 183 then dbms_types.typecode_interval_ds
end
, desc_tab( numcols ).col_precision
, desc_tab( numcols ).col_scale
, case desc_tab( numcols ).col_type
when 11 then 18 -- for rowid col_max_len = 16, and 18 characters are shown
else desc_tab( numcols ).col_max_len
end
, desc_tab( numcols ).col_charsetid
, desc_tab( numcols ).col_charsetform
);
end loop;
close rc;
atyp.endcreate;
anytype.begincreate( dbms_types.typecode_table, rtype );
rtype.SetInfo( null, null, null, null, null, atyp, dbms_types.typecode_object, 0 );
rtype.endcreate();
return odciconst.success;
exception
when others then
return odciconst.error;
end;
--
static function ODCITablePrepare( sctx out PivotImpl, ti in sys.ODCITabFuncInfo, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number )
return number
is
prec pls_integer;
scale pls_integer;
len pls_integer;
csid pls_integer;
csfrm pls_integer;
elem_typ anytype;
aname varchar2(30);
tc pls_integer;
begin
tc := ti.RetType.GetAttrElemInfo( 1, prec, scale, len, csid, csfrm, elem_typ, aname );
--
if instr( p_fmt, ‘@[email protected]‘ ) > 0
then
sctx := PivotImpl( elem_typ, p_stmt, p_fmt, null );
else
sctx := PivotImpl( elem_typ, p_stmt, ‘@[email protected]‘, null );
end if;
return odciconst.success;
end;
--
static function ODCITableStart( sctx in out PivotImpl, p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number )
return number
is
cur integer;
numcols number;
desc_tab dbms_sql.desc_tab2;
t_stmt varchar2(32767);
type_code pls_integer;
prec pls_integer;
scale pls_integer;
len pls_integer;
csid pls_integer;
csfrm pls_integer;
schema_name varchar2(30);
type_name varchar2(30);
version varchar2(30);
attr_count pls_integer;
attr_type anytype;
attr_name varchar2(100);
dummy2 integer;
begin
cur := dbms_sql.open_cursor;
dbms_sql.parse( cur, p_stmt, dbms_sql.native );
dbms_sql.describe_columns2( cur, numcols, desc_tab );
dbms_sql.close_cursor( cur );
--
for i in 1 .. numcols - 2
loop
t_stmt := t_stmt || ‘, "‘ || desc_tab( i ).col_name || ‘"‘;
end loop;
--
type_code := sctx.ret_type.getinfo( prec
, scale
, len
, csid
, csfrm
, schema_name
, type_name
, version
, attr_count
);
for i in numcols - 1 .. attr_count
loop
type_code := sctx.ret_type.getattreleminfo( i
, prec
, scale
, len
, csid
, csfrm
, attr_type
, attr_name
);
t_stmt := t_stmt || replace( ‘, max( decode( ‘ || sctx.fmt || ‘, ‘‘‘ || attr_name || ‘‘‘, ‘ || desc_tab( numcols ).col_name || ‘ ) )‘
, ‘@[email protected]‘
, desc_tab( numcols - 1 ).col_name
);
end loop;
t_stmt := ‘select ‘ || substr( t_stmt, 2 ) || ‘ from ( ‘ || sctx.stmt || ‘ )‘;
for i in 1 .. numcols - 2
loop
if i = 1
then
t_stmt := t_stmt || ‘ group by "‘ || desc_tab( i ).col_name || ‘"‘;
else
t_stmt := t_stmt || ‘, "‘ || desc_tab( i ).col_name || ‘"‘;
end if;
end loop;
--
--dbms_output.put_line( t_stmt );
sctx.cur := dbms_sql.open_cursor;
dbms_sql.parse( sctx.cur, t_stmt, dbms_sql.native );
for i in 1 .. attr_count
loop
type_code := sctx.ret_type.getattreleminfo( i
, prec
, scale
, len
, csid
, csfrm
, attr_type
, attr_name
);
case type_code
when dbms_types.typecode_char then dbms_sql.define_column( sctx.cur, i, ‘x‘, 32767 );
when dbms_types.typecode_varchar2 then dbms_sql.define_column( sctx.cur, i, ‘x‘, 32767 );
when dbms_types.typecode_number then dbms_sql.define_column( sctx.cur, i, cast( null as number ) );
when dbms_types.typecode_date then dbms_sql.define_column( sctx.cur, i, cast( null as date ) );
when dbms_types.typecode_urowid then dbms_sql.define_column( sctx.cur, i, cast( null as urowid ) );
when dbms_types.typecode_timestamp then dbms_sql.define_column( sctx.cur, i, cast( null as timestamp ) );
when dbms_types.typecode_timestamp_tz then dbms_sql.define_column( sctx.cur, i, cast( null as timestamp with time zone ) );
when dbms_types.typecode_timestamp_ltz then dbms_sql.define_column( sctx.cur, i, cast( null as timestamp with local time zone ) );
when dbms_types.typecode_interval_ym then dbms_sql.define_column( sctx.cur, i, cast( null as interval year to month ) );
when dbms_types.typecode_interval_ds then dbms_sql.define_column( sctx.cur, i, cast( null as interval day to second ) );
end case;
end loop;
dummy2 := dbms_sql.execute( sctx.cur );
return odciconst.success;
end;
--
member function ODCITableFetch( self in out PivotImpl, nrows in number, outset out anydataset )
return number
is
c1_col_type pls_integer;
type_code pls_integer;
prec pls_integer;
scale pls_integer;
len pls_integer;
csid pls_integer;
csfrm pls_integer;
schema_name varchar2(30);
type_name varchar2(30);
version varchar2(30);
attr_count pls_integer;
attr_type anytype;
attr_name varchar2(100);
v1 varchar2(32767);
n1 number;
d1 date;
ur1 urowid;
ids1 interval day to second;
iym1 interval year to month;
ts1 timestamp;
tstz1 timestamp with time zone;
tsltz1 timestamp with local time zone;
begin
outset := null;
if nrows < 1
then
-- is this possible???
return odciconst.success;
end if;
--
--dbms_output.put_line( ‘fetch‘ );
if dbms_sql.fetch_rows( self.cur ) = 0
then
return odciconst.success;
end if;
--
--dbms_output.put_line( ‘done‘ );
type_code := self.ret_type.getinfo( prec
, scale
, len
, csid
, csfrm
, schema_name
, type_name
, version
, attr_count
);
anydataset.begincreate( dbms_types.typecode_object, self.ret_type, outset );
outset.addinstance;
outset.piecewise();
for i in 1 .. attr_count
loop
type_code := self.ret_type.getattreleminfo( i
, prec
, scale
, len
, csid
, csfrm
, attr_type
, attr_name
);
--dbms_output.put_line( attr_name );
case type_code
when dbms_types.typecode_char then
dbms_sql.column_value( self.cur, i, v1 );
outset.setchar( v1 );
when dbms_types.typecode_varchar2 then
dbms_sql.column_value( self.cur, i, v1 );
outset.setvarchar2( v1 );
when dbms_types.typecode_number then
dbms_sql.column_value( self.cur, i, n1 );
outset.setnumber( n1 );
when dbms_types.typecode_date then
dbms_sql.column_value( self.cur, i, d1 );
outset.setdate( d1 );
when dbms_types.typecode_urowid then
dbms_sql.column_value( self.cur, i, ur1 );
outset.seturowid( ur1 );
when dbms_types.typecode_interval_ds then
dbms_sql.column_value( self.cur, i, ids1 );

outset.setintervalds( ids1 );
when dbms_types.typecode_interval_ym then
dbms_sql.column_value( self.cur, i, iym1 );
outset.setintervalym( iym1 );
when dbms_types.typecode_timestamp then
dbms_sql.column_value( self.cur, i, ts1 );
outset.settimestamp( ts1 );
when dbms_types.typecode_timestamp_tz then
dbms_sql.column_value( self.cur, i, tstz1 );
outset.settimestamptz( tstz1 );
when dbms_types.typecode_timestamp_ltz then
dbms_sql.column_value( self.cur, i, tsltz1 );
outset.settimestampltz( tsltz1 );
end case;
end loop;
outset.endcreate;
return odciconst.success;
end;
--
member function ODCITableClose( self in PivotImpl )
return number
is
c integer;
begin
c := self.cur;
dbms_sql.close_cursor( c );
return odciconst.success;
end;
end;
/

-- 在外面包装一层PLSQL函数：
create or replace
function pivot( p_stmt in varchar2, p_fmt in varchar2 := ‘upper(@[email protected])‘, dummy in number := 0 )
return anydataset pipelined using PivotImpl;
/

 

用这个神奇的pivot函数的写法：
select *
from   table( pivot(‘select deptno
                      ,      job
                      ,      avg(sal) sal_avg
                      from   scott.emp
                      group
                      by     deptno
                      ,      job
                    ‘)
            );