I have a sample of the table and problem I am trying to solve in Oracle.
CREATE TABLE mytable (
id_field number
,status_code number
,desc1 varchar2(15)
);
INSERT INTO mytable VALUES (1,240,'desc1');
INSERT INTO mytable VALUES (2,242,'desc1');
INSERT INTO mytable VALUES (3,241,'desc1');
INSERT INTO mytable VALUES (4,244,'desc1');
INSERT INTO mytable VALUES (5,240,'desc2');
INSERT INTO mytable VALUES (6,242,'desc2');
INSERT INTO mytable VALUES (7,245,'desc2');
INSERT INTO mytable VALUES (8,246,'desc2');
INSERT INTO mytable VALUES (9,246,'desc1');
INSERT INTO mytable VALUES (10,242,'desc1');
commit;
SELECT *
FROM mytable
WHERE status_code IN CASE WHEN desc1 = 'desc1' THEN (240,242)
WHEN desc1 = 'desc2' THEN (240,245)
END
Basically I need to select a subset of status codes for each condition.
I could solve this with separate statements but the actual table I am doing this on has multiple descriptions and would result in around 20 unioned queries.
Any way to do this in one statement like I have attempted?
I believe that a CASE statement can only return one value (corresponding to one column in the result set). However, you can achive this in your WHERE clause without using a CASE statement:
WHERE (desc1 = 'desc1' AND status_code IN (240,242)) OR
(desc1 = 'desc2' AND status_code IN (240,245))
I like Tim answer better, but at least in postgres you can do this. Couldnt try it on oracle
Sql Fiddle DEMO
SELECT *
FROM mytable
WHERE CASE WHEN desc1 = 'desc1' THEN status_code IN (240,242)
WHEN desc1 = 'desc2' THEN status_code IN (240,245)
END
ORDER BY desc1
OUTPUT
| id_field | status_code | desc1 |
|----------|-------------|-------|
| 1 | 240 | desc1 |
| 2 | 242 | desc1 |
| 10 | 242 | desc1 |
| 5 | 240 | desc2 |
| 7 | 245 | desc2 |
Related
I have a table with 2 columns
item_name varchar2
brand varchar2
both of them have bitmap index
let's say I create a view for a specific brand and rename the column item_name ,something like that
create view my_brand as
select item_name as item from table x where brand='x'
We cannot create an index on a normal view but what is Oracle doing when issuing the underlying query of that view? Is the index of the item_name column being used if we write select item from my_brand where item='item1'?
thanks
The answer will be “it depends”. The index access path is certainly an option open to the optimizer; but remember that the optimizer makes a cost based decision. So essentially it will evaluate the cost of all the available plans and choose the one with the lowest cost.
Here is an example:
create table tab1 ( item_name varchar2(15), brand varchar2(15) );
insert into tab1
select 'Name '||to_char( rownum), 'Brand '||to_char(mod(rownum,10))
from dual
connect by rownum < 1000000
commit;
exec dbms_stats.gather_table_stats( user, 'TAB1' );
create bitmap index bm1 on tab1 ( item_name );
create bitmap index bm2 on tab1 ( brand );
create or replace view my_brand
as select item_name as item from tab1 where brand = 'Brand 1';
explain plan for
select item from my_brand where item = 'Name 1001'
select * from table( dbms_xplan.display )
--------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 20 | 3 (0)| 00:00:01 |
|* 1 | TABLE ACCESS BY INDEX ROWID BATCHED| TAB1 | 1 | 20 | 3 (0)| 00:00:01 |
| 2 | BITMAP CONVERSION TO ROWIDS | | | | | |
|* 3 | BITMAP INDEX SINGLE VALUE | BM1 | | | | |
--------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("BRAND"='Brand 1')
3 - access("ITEM_NAME"='Name 1001')
We can create an index on a normal view
No, you can't
SQL> create table as_idx_view (item_name varchar2(10), brand varchar2(10));
Table created.
SQL> create view as_view as select item_name item from as_idx_view where brand = 'X';
View created.
SQL> create index as_idx_view_idx1 on as_view (item);
create index as_idx_view_idx1 on as_view (item)
*
ERROR at line 1:
ORA-01702: a view is not appropriate here
I would like to analyze table usage on Verica to check the following
the tables that are hit most be queries
tables that are getting more write queries
tables that are getting more read queries.
So I am asking for help for SQL query or if anyone has any documents please point me in right direction. Thank you.
Here, I create a function QTYPE() that assigns a request of type 'QUERY' to either a SELECT, an INSERT, or a MODIFY (meaning DELETE,UPDATE,MERGE). The differentiation comes from the fact that, in Vertica, UPDATE/MERGE are actually DELETEs, then INSERTs.
I use two regular expressions of a certain complexity: first, finding [schema.]tablename after a JOIN or FROM keyword, then finding [schema.]tablename after either the UPDATE, the INSERT INTO, the MERGE INTO and the DELETE FROM keywords. Then, I join back to the tables system table to a) only select the tables really existing and b) add the schema name if it is missing.
The final report would be:
qtype | tbname | tx_count
--------+------------------------------------------------------+----------
INSERT | dbadmin.nrm_cpustats_rate | 74
INSERT | dbadmin.v_poll_item | 39
INSERT | dbadmin.child | 32
INSERT | dbadmin.tbid | 32
INSERT | dbadmin.etl_group_membership | 12
INSERT | dbadmin.sensor_oco | 11
INSERT | webanalytics.webtraffic_part | 10
INSERT | webanalytics.webtraffic_new_design_platform_datadate | 9
MODIFY | cp.foo | 2
MODIFY | public.foo | 2
MODIFY | taboola_tests.foo | 2
SELECT | dbadmin.flext | 112
SELECT | dbadmin.children | 112
SELECT | dbadmin.ffoo | 112
SELECT | dbadmin.demovals | 112
SELECT | dbadmin.allbut4 | 112
SELECT | dbadmin.allcols | 112
SELECT | dbadmin.allbut1 | 112
SELECT | dbadmin.flx | 112
Here's the function definition, and the CREATE TABLE statement to collect the statistics of what you're looking for, and finally the query getting the 'hit parade' of the most touched tables ...
Mind you, it might become a long runner with a lot of history in your query_requests table ...
CREATE OR REPLACE FUNCTION qtype(sql VARCHAR(64000))
RETURN VARCHAR(8) AS BEGIN
RETURN
CASE UPPER(REGEXP_SUBSTR(sql,'\w+')::VARCHAR(16))
WHEN 'SELECT' THEN 'SELECT'
WHEN 'WITH' THEN 'SELECT'
WHEN 'AT' THEN 'SELECT'
WHEN 'INSERT' THEN 'INSERT'
WHEN 'DELETE' THEN 'MODIFY'
WHEN 'UPDATE' THEN 'MODIFY'
WHEN 'MERGE' THEN 'MODIFY'
ELSE UPPER(REGEXP_SUBSTR(sql,'\w+')::VARCHAR(16))
END
;
END;
DROP TABLE IF EXISTS table_op_stats;
CREATE TABLE table_op_stats AS
WITH
-- need 1000 integers - up to ~400 source tables found in 1 select
i(i) AS (
SELECT MICROSECOND(tm)
FROM (
SELECT TIMESTAMPADD(MICROSECOND, 1,'2000-01-01'::TIMESTAMP)
UNION ALL SELECT TIMESTAMPADD(MICROSECOND,1000,'2000-01-01'::TIMESTAMP)
) l(ts)
TIMESERIES tm AS '1 MICROSECOND' OVER(ORDER BY ts)
)
,
tblist AS (
-- selects can affect several types, found by JOIN or FROM keyword before
-- hence look_behind regular expression
SELECT
QTYPE(request) AS qtype
, transaction_id
, statement_id
, i
, LTRIM(REGEXP_SUBSTR(request,'(?<=(from|join))\s+(\w+\.)?\w+\b',1,i,'i')) as tbname
FROM query_requests CROSS JOIN i
WHERE request_type='QUERY'
AND success
AND LTRIM(REGEXP_SUBSTR(request,'(?<=(from|join))\s+(\w+\.)?\w+\b',1,i,'i')) <> ''
UNION ALL
-- insert/delete/update/merge queries only affect one table each
SELECT
QTYPE(request) AS qtype
, transaction_id
, statement_id
, 1 AS i
, LTRIM(REGEXP_SUBSTR(request,'(insert\s+.*into\s+|update\s+.*|merge\s+.*into|delete\s+.*from)\s*((\w+\.)?\w+)\b',1,1,'i',2)) as tbname
FROM query_requests
WHERE request_type='QUERY'
AND success
AND QTYPE(request) <> 'SELECT'
)
,
-- join back to the "tables" system table - removes queries from correlation names, and adds schema name if needed
real_tables AS (
SELECT
qtype
, transaction_id
, statement_id
, i
, CASE WHEN SPLIT_PART(tbname,'.',2)=''
THEN table_schema||'.'||tbname
ELSE tbname
END AS tbname
FROM tblist
JOIN tables ON CASE WHEN SPLIT_PART(tbname,'.',2)=''
THEN tbname=table_name
ELSE SPLIT_PART(tbname,'.',1)=table_schema AND SPLIT_PART(tbname,'.',2)=table_name
END
)
SELECT
qtype
, transaction_id
, statement_id
, i
, tbname
FROM real_tables;
-- Time: First fetch (0 rows): 42483.769 ms. All rows formatted: 42484.324 ms
-- the query at the end:
WITH grp AS (
SELECT
qtype
, tbname
, COUNT(*) AS tx_count
FROM table_op_stats
GROUP BY 1,2
)
SELECT
*
FROM grp
LIMIT 8 OVER(
PARTITION BY qtype
ORDER BY tx_count DESC
);
I have a requirement in Oracle SQL that specific values should be repeated 5 times. So, I have written the below query and getting the result as expected.
SELECT Item_Name || RANGES AS Item_Number
FROM
(
SELECT DISTINCT 'Price Line ' || column1 || '-' AS Item_Name, level+0 RANGES
FROM
(
SELECT DISTINCT column1 from tbl where column1 in
(
'ABC',
'BCD'
)
) connect by level <= 5
) order by Item_Number
OUTPUT:
Price Line ABC-1
Price Line ABC-2
Price Line ABC-3
Price Line ABC-4
Price Line ABC-5
Price Line BCD-1
Price Line BCD-2
Price Line BCD-3
Price Line BCD-4
Price Line BCD-5
But when I add more than 10 values like 'DEF', 'EFG',.....'XYZ', the query keeps executing for hours without any result.
Any help or suggestion on this would be appreciated.
Regards,
Make sure the CONNECT BY is not operating on your table rows. For example, use a common table expression (i.e., a WITH clause) to create a row source with 5 rows using CONNECT BY and then CROSS JOIN that row source to your table. Here is an example.
CREATE TABLE ITEMS ( item_number VARCHAR2(30) );
INSERT INTO ITEMS VALUES ('ABC');
INSERT INTO ITEMS VALUES ('BCD');
INSERT INTO ITEMS VALUES ('CDE');
INSERT INTO ITEMS VALUES ('DEF');
INSERT INTO ITEMS VALUES ('EFG');
INSERT INTO ITEMS VALUES ('FGH');
INSERT INTO ITEMS VALUES ('GHI');
INSERT INTO ITEMS VALUES ('HIJ');
INSERT INTO ITEMS VALUES ('IJK');
INSERT INTO ITEMS VALUES ('JKL');
COMMIT;
WITH rowgen AS (
SELECT rownum rn FROM dual CONNECT BY rownum <= 5 )
SELECT item_number || '-' || rn
FROM items
CROSS JOIN rowgen
ORDER BY item_number, rn;
+----------------------+
| ITEM_NUMBER||'-'||RN |
+----------------------+
| ABC-1 |
| ABC-2 |
| ABC-3 |
| ABC-4 |
| ABC-5 |
| BCD-1 |
| BCD-2 |
| BCD-3 |
| BCD-4 |
| BCD-5 |
| CDE-1 |
| CDE-2 |
| CDE-3 |
| CDE-4 |
| CDE-5 |
| ... |
+----------------------+
First of all, I would like to THANK YOU for stopping by and spending your precious time for looking at my problem.
I have 2 different tables within an Oracle Database.
The first table holds metadata about the columns present in the other table. Think of the first (COL_TAB) table as a custom version of the ALL_TAB_COLS which comes by default with Oracle.
COL_TAB
----------------------------------------------
| TABLE_NAME | COL_NAME | COL_DESC |
----------------------------------------------
| TABLE1 | TAB1_COL_2 | TABLE 1 COLUMN 2 |
| TABLE1 | TAB1_COL_4 | TABLE 1 COLUMN 4 |
| TABLE1 | TAB1_COL_3 | TABLE 1 COLUMN 3 |
| TABLE1 | TAB1_COL_5 | |
| TABLE1 | TAB1_COL_1 | TABLE 1 COLUMN 1 |
----------------------------------------------
TABLE1
--------------------------------------------------------------------
| TAB1_COL_3 | TAB1_COL_1 | TAB1_COL_5 | TAB1_COL_2 |
--------------------------------------------------------------------
| TAB1_COL3_DATA1 | TAB1_COL1_DAT | TAB1_COL5_DAT2 | TAB1_COL2_DAT |
| TAB1_COL3_DATA2 | TAB1_COL1_DAT | TAB1_COL5_DAT1 | TAB1_COL2_DAT |
| TAB1_COL3_DATA3 | TAB1_COL1_DAT | TAB1_COL5_DAT3 | TAB1_COL2_DAT |
--------------------------------------------------------------------
I want to display the data as 2 different outputs:
FIRST OUTPUT:
------------------------------------------------------------------------------------------------
| TABLE 1 COLUMN 3 | TABLE 1 COLUMN 1 | TAB1_COL_5 | TABLE 1 COLUMN 2 | TABLE 1 COLUMN 4 |
------------------------------------------------------------------------------------------------
-> In case, if the COL_DESC is blank or null, then the COL_NAME needs to be displayed in the output.
-> "TABLE 1 COLUMN 3" AND "TABLE 1 COLUMN 1" always need to be displayed as 1st and 2nd column followed by the rest of the columns.
-> In case, if any column defined within the COL_TAB table isn't being used in TABLE1, then such a column needs to be displayed at the last column in the output,
for example, the TAB1_COL_4 isn't being used in TABLE1, so it is being displayed in the last.
SECOND OUTPUT:
------------------------------------------------------------------------------------------------
| TAB1_COL3_DATA1 | TAB1_COL1_DAT | TAB1_COL5_DAT2 | TAB1_COL2_DAT | |
| TAB1_COL3_DATA2 | TAB1_COL1_DAT | TAB1_COL5_DAT1 | TAB1_COL2_DAT | |
| TAB1_COL3_DATA3 | TAB1_COL1_DAT | TAB1_COL5_DAT3 | TAB1_COL2_DAT | |
------------------------------------------------------------------------------------------------
-> The order of the COLUMNS in the SECOND OUTPUT needs to be in sync with the order of columns as displayed within in the FIRST OUTPUT.
I did try the below query for displaying the FIRST OUTPUT, but it isn't working (I'm sure it's not correct):
SELECT NVL(COL_DESC, COL_NAME) AS COL_TEXT
FROM COL_TAB
WHERE TABLE_NAME = 'TABLE1'
PIVOT(MIN(COL_TEXT)
FOR COL_TEXT IN (SELECT COL_NAME FROM COL_TAB WHERE TABLE_NAME = 'TABLE1'));
In case, if anything isn't clear please do let me know. I would try my best to explain it again. Thanks again for your help in advance.
You can get the column description/names - in a deterministic order - with something like:
select coalesce(ct.col_desc, ct.col_name)
from col_tab ct
left join user_tab_columns utc
on utc.table_name = ct.table_name and utc.column_name = ct.col_name
where ct.table_name = 'TABLE1'
order by utc.column_id, ct.col_name;
COALESCE(CT.COL_
----------------
TABLE 1 COLUMN 3
TABLE 1 COLUMN 1
TAB1_COL_5
TABLE 1 COLUMN 2
TABLE 1 COLUMN 4
Pivoting those rows to columns would need to be done dynamically.
You can also generate a dynamic query to get the data in the same order in a similar way.
This uses SQL*Plus (or SQLcl, or SQL Developer) bind variable ref cursors to get the two outputs, and uses a table name defined within the block; but could easily be adapted to be a procedure that is passed the table name and have out parameters for the ref cursors:
var rc1 refcursor;
var rc2 refcursor;
declare
l_table_name varchar2(30) := 'TABLE1';
l_stmt varchar2(4000);
begin
select 'select '
|| listagg('''' || coalesce(ct.col_desc, ct.col_name) || '''', ',')
within group (order by utc.column_id, ct.col_name)
|| ' from dual'
into l_stmt
from col_tab ct
left join user_tab_columns utc
on utc.table_name = ct.table_name and utc.column_name = ct.col_name
where ct.table_name = l_table_name;
dbms_output.put_line(l_stmt);
open :rc1 for l_stmt;
select 'select '
|| listagg(coalesce(utc.column_name, 'null') || ' as ' || ct.col_name, ',')
within group (order by utc.column_id, ct.col_name)
|| ' from ' || l_table_name
into l_stmt
from col_tab ct
left join user_tab_columns utc
on utc.table_name = ct.table_name and utc.column_name = ct.col_name
where ct.table_name = l_table_name;
dbms_output.put_line(l_stmt);
open :rc2 for l_stmt;
end;
/
Running the block gets dbms_output of the statements just for debugging, but might be of interest:
select 'TABLE 1 COLUMN 3','TABLE 1 COLUMN 1','TAB1_COL_5','TABLE 1 COLUMN 2','TABLE 1 COLUMN 4' from dual
select TAB1_COL_3 as TAB1_COL_3,TAB1_COL_1 as TAB1_COL_1,TAB1_COL_5 as TAB1_COL_5,TAB1_COL_2 as TAB1_COL_2,null as TAB1_COL_4 from TABLE1
and then you can print the ref cursors (again, client-specific behaviour):
print rc1
'TABLE1COLUMN3' 'TABLE1COLUMN1' 'TAB1_COL_ 'TABLE1COLUMN2' 'TABLE1COLUMN4'
---------------- ---------------- ---------- ---------------- ----------------
TABLE 1 COLUMN 3 TABLE 1 COLUMN 1 TAB1_COL_5 TABLE 1 COLUMN 2 TABLE 1 COLUMN 4
print rc2
TAB1_COL_3 TAB1_COL_1 TAB1_COL_5 TAB1_COL_2 TAB1_COL_4
--------------- ------------- -------------- ------------- ----------
TAB1_COL3_DATA1 TAB1_COL1_DAT TAB1_COL5_DAT2 TAB1_COL2_DAT
TAB1_COL3_DATA2 TAB1_COL1_DAT TAB1_COL5_DAT1 TAB1_COL2_DAT
TAB1_COL3_DATA3 TAB1_COL1_DAT TAB1_COL5_DAT3 TAB1_COL2_DAT
Those 2 columns are common across all the tables.
In that case you can use a case expression to extend the ordering logic:
within group (order by case ct.col_name
when 'TAB1_COL_3' then 1
when 'TAB1_COL_1' then 2
else 3 end,
utc.column_id, ct.col_name)
which then gets:
'TABLE1COLUMN3' 'TABLE1COLUMN1' 'TAB1_COL_ 'TABLE1COLUMN2' 'TABLE1COLUMN4'
---------------- ---------------- ---------- ---------------- ----------------
TABLE 1 COLUMN 3 TABLE 1 COLUMN 1 TAB1_COL_5 TABLE 1 COLUMN 2 TABLE 1 COLUMN 4
TAB1_COL_3 TAB1_COL_1 TAB1_COL_5 TAB1_COL_2 TAB1_COL_4
--------------- ------------- -------------- ------------- ----------
TAB1_COL3_DATA1 TAB1_COL1_DAT TAB1_COL5_DAT2 TAB1_COL2_DAT
TAB1_COL3_DATA2 TAB1_COL1_DAT TAB1_COL5_DAT1 TAB1_COL2_DAT
TAB1_COL3_DATA3 TAB1_COL1_DAT TAB1_COL5_DAT3 TAB1_COL2_DAT
or possibly using the description instead of the name, depending on whether it's the name or description that stays the same (hard to guess from the example).
It would be really great if you could show up how pivoting can be done dynamically.
it isn't really needed here in the end, and is more complicated than the listagg I used above; but you could do something like;
select '
select * from (
select row_number()
over (order by case ct.col_name
when ''TAB1_COL_3'' then 1
when ''TAB1_COL_1'' then 2
else 3
end,
utc.column_id, ct.col_name) as pos,
coalesce(ct.col_desc, ct.col_name) as name
from col_tab ct
left join user_tab_columns utc
on utc.table_name = ct.table_name and utc.column_name = ct.col_name
where ct.table_name = :tab
)
pivot (max(name) as col for (pos) in ('
|| listagg(level, ',') within group (order by level)
|| '))'
into l_stmt
from dual
connect by level <= (select count(*) from col_tab where table_name = l_table_name);
dbms_output.put_line(l_stmt);
open :rc1 for l_stmt using l_table_name;
which gets output showing the generated dynamic query as:
select * from (
select row_number()
over (order by case ct.col_name
when 'TAB1_COL_3' then 1
when 'TAB1_COL_1' then 2
else 3
end,
utc.column_id, ct.col_name) as pos,
coalesce(ct.col_desc, ct.col_name) as name
from col_tab ct
left join user_tab_columns utc
on utc.table_name = ct.table_name and utc.column_name = ct.col_name
where ct.table_name = :tab
)
pivot (max(name) as col for (pos) in (1,2,3,4,5))
and result set as:
1_COL 2_COL 3_COL 4_COL 5_COL
---------------- ---------------- ---------------- ---------------- ----------------
TABLE 1 COLUMN 3 TABLE 1 COLUMN 1 TAB1_COL_5 TABLE 1 COLUMN 2 TABLE 1 COLUMN 4
You could use the column names for the pivot instead of the pos, it would just make it even harder to read I think, as you'd need to include quotes around them.
select distinct employee_id, first_name, commission_pct, department_id from
employees;
When I use the above query it results in distinct combination of all the attributes mentioned. As employee_id (being the primary key for employees) is unique, the query results in producing all the rows in the table.
I want to have a result set that has distinct combination of commission_pct and department_id. so how the query should be formed. When I tried to include the DISTINCT in the middle as
select employee_id, first_name, distinct commission_pct, department_id from
employees;
It is resulting in an error
ORA-00936-missing expression
How to form a query which results have only distinct combination of commission and department_id.The table is from HR schema of oracle.
What you request is impossible. You cannot select all the employee ids but have only distinct commission_pct and department_id.
So think it over, what you want to show:
All distinct commission_pct, department_id only?
All distinct commission_pct, department_id and the number of relevant employees?
All distinct commission_pct, department_id and the relevant employees comma separated?
All employees, but with nulls when commission_pct and department_id are the same as in the line before?
The first can be solved with DISTINCT. The second and third with GROUP BY (plus count or listagg). The last would be solved with the analytic function LAG.
You have to remove two columns before distinct
select distinct commission_pct, department_id from
employees;
Indeed, if your second query would work, what do you expect to see in the first two columns? Consider example data
| employee_id | first_name | commission_pct | department_id |
| 1 | "x" | "b" | 3 |
| 2 | "y" | "b" | 3 |
| 1 | "x" | "c" | 4 |
| 2 | "y" | "c" | 4 |
You expect to get only two row result like this
| employee_id | first_name | commission_pct | department_id |
| ? | ? | "b" | 3 |
| ? | ? | "c" | 4 |
But what do you expect in the first two column?
Can you try this one?
SELECT
NAME1,
PH
FROM
(WITH T
AS (SELECT
'mark' NAME1,
'1234567' PH
FROM
DUAL
UNION ALL
SELECT
'bailey',
'456789'
FROM
DUAL
UNION ALL
SELECT
'mark',
'987654'
FROM
DUAL)
SELECT
NAME1,
PH,
ROW_NUMBER ( ) OVER (PARTITION BY NAME1 ORDER BY NAME1) SEQ
FROM
T)
WHERE
SEQ = 1;
If you dont care on a specific row, then use aggregate functions
SELECT
NAME1,
MAX ( PH ) PH
FROM
T
GROUP BY
NAME1;