-- 准备环境
create table t1(id int,name varchar2(100));
begin
for i in 1001..10000 loop
insert into t1 values(i,‘china‘||to_char(i));
end loop;
commit;
end;
-- 创建函数
create or replace function f_display_raw(rawval raw, type varchar2)
return varchar2 is
cn number;
cv varchar2(32);
cd date;
cnv nvarchar2(32);
cr rowid;
cc char(32);
cbf binary_float;
cbd binary_double;
begin
if (type = ‘VARCHAR2‘) then
dbms_stats.convert_raw_value(rawval, cv);
return to_char(cv);
elsif (type = ‘DATE‘) then
dbms_stats.convert_raw_value(rawval, cd);
return to_char(cd,‘yyyy-MM-dd‘);
elsif (type = ‘NUMBER‘) then
dbms_stats.convert_raw_value(rawval, cn);
return to_char(cn);
elsif (type = ‘BINARY_FLOAT‘) then
dbms_stats.convert_raw_value(rawval, cbf);
return to_char(cbf);
elsif (type = ‘BINARY_DOUBLE‘) then
dbms_stats.convert_raw_value(rawval, cbd);
return to_char(cbd);
elsif (type = ‘NVARCHAR2‘) then
dbms_stats.convert_raw_value(rawval, cnv);
return to_char(cnv);
elsif (type = ‘ROWID‘) then
dbms_stats.convert_raw_value(rawval, cr);
return to_char(cr);
elsif (type = ‘CHAR‘) then
dbms_stats.convert_raw_value(rawval, cc);
return to_char(cc);
else
return ‘UNKNOWN DATATYPE‘;
end if;
end;
--分析统计信息
analyze table T1 compute statistics for table;
analyze table T1 compute statistics for all columns;
-- 查看
select a.column_name,
f_display_raw(a.low_value, b.data_type) as low_val,
f_display_raw(a.high_value, b.data_type) as high_val,
b.data_type
from user_tab_col_statistics a, user_tab_cols b
where a.table_name = ‘T1‘
and a.table_name = b.table_name
and a.column_name = b.column_name;
oracle 查看列统计信息中 low_value