Oracle: Capitalizing and removing underscores from a column name

Oracle table names are all caps with underscores.  So if you're consuming them from something like all_tab_columns, this quick little function makes them a little prettier. 

select initcap(replace(lower('SOME_COLUMN_NAME'),'_',' ')) from dual;

Oracle: Obtaining a date for a given business day in a month.

Oracle SQL to get the date for a given business day in a passed in month, sysdate used for example.

With a as(
SELECT
  trunc(sysdate,'MM')- 1 + level AS day
 ,to_number(to_char(trunc(sysdate,'MM')- 1 + level,'D'))  as weekday
 ,rownum as business_day
FROM
  dual
  where to_char(trunc(sysdate,'MM')- 1 + level,'D') not in (1,7)
  -- add in a check for a holday calendar here
CONNECT BY LEVEL between 1 and EXTRACT(day from last_day(sysdate)) 
)
select a.day  from a where business_day = 5

Oracle: Looking at the cursor metadata

Based on information provided at https://boobalganesan.blogspot.com/2017/08/dbmssqldescribecolumns-tips.html here are a few steps for dumping out cursor meta data returned from a stored proc.

first, create a global temp table

 CREATE GLOBAL TEMPORARY TABLE desc_col_test
    (
    col_id NUMBER(10),
    col_desc VARCHAR2(255)
);

then run this block

declare
    
   O_RES SYS_REFCURSOR;

    v_cursor_number number;
    v_columns number;
    v_desc_tab dbms_sql.desc_tab;

begin
  
delete from desc_col_test;

 --Adust to your variables accordingly 
YOUR_SCHEMA.YOUR_PKG_YOUR_PROD(p_dt => TO_DATE ('31-12-2018 00:00:00', 'DD-MM-YYYY HH24:MI:SS'), o_res => O_RES);

v_cursor_number := dbms_sql.to_cursor_number(rc => O_RES);
    --Get information on the columns
    dbms_sql.describe_columns(v_cursor_number, v_columns, v_desc_tab);
--Loop through all the columns, find COLUMN1 position and type
    for i in 1 .. v_desc_tab.count loop
      
INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_name:'||decode(v_desc_tab(i).col_name, Null, 'Null', v_desc_tab(i).col_name));

INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_type: ' ||
 case
                 when v_desc_tab(i).col_type = 1 then 'VARCHAR2'
                 when v_desc_tab(i).col_type = 2 then 'NUMBER'
                 when v_desc_tab(i).col_type = 8 then 'LONG'
                 when v_desc_tab(i).col_type =  9 then 'VARCHAR'
                 when v_desc_tab(i).col_type =  12 then 'DATE'
                 when v_desc_tab(i).col_type =  23 then 'RAW'
                 when v_desc_tab(i).col_type =  69 then 'ROWID'
                 when v_desc_tab(i).col_type =  96 then 'CHAR'
                 when v_desc_tab(i).col_type =  100 then 'BINARY_FLOAT'
                 when v_desc_tab(i).col_type =  101 then 'BINARY_DOUBLE'
                 when v_desc_tab(i).col_type =  105 then 'MLSLABEL'
                 when v_desc_tab(i).col_type =  106 then 'MLSLABEL'
                 when v_desc_tab(i).col_type =  112 then  'CLOB'
                 when v_desc_tab(i).col_type =  113 then 'BLOB'
                 when v_desc_tab(i).col_type =  114 then 'BFILE'
                 when v_desc_tab(i).col_type =  115 then 'CFILE'
                 when v_desc_tab(i).col_type =  178 then 'TIME'
                 when v_desc_tab(i).col_type =  179 then 'TIME WITH TIME ZONE'
                 when v_desc_tab(i).col_type =  180 then 'TIMESTAMP'
                 when v_desc_tab(i).col_type =  181 then 'TIMESTAMP WITH TIME ZONE'
                 when v_desc_tab(i).col_type =  231 then 'TIMESTAMP WITH LOCAL TIME ZONE'
                 when v_desc_tab(i).col_type =  182 then 'INTERVAL YEAR TO MONTH'
                 when v_desc_tab(i).col_type =  183 then 'INTERVAL DAY TO SECOND'
                 else 'OTHER' end);


 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_precision:'||decode(v_desc_tab(i).col_precision, Null, 'Null', v_desc_tab(i).col_precision));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_max_len:'||decode(v_desc_tab(i).col_max_len, Null, 'Null', v_desc_tab(i).col_max_len));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_name_len:'||decode(v_desc_tab(i).col_name_len, Null, 'Null', v_desc_tab(i).col_name_len));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_schema_name:'||decode(v_desc_tab(i).col_schema_name, Null, 'Null', v_desc_tab(i).col_schema_name));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_schema_name_len:'||decode(v_desc_tab(i).col_schema_name_len, Null, 'Null', v_desc_tab(i).col_schema_name_len));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_scale:'||decode(v_desc_tab(i).col_scale, Null, 'Null', v_desc_tab(i).col_scale));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_charsetid:'||decode(v_desc_tab(i).col_charsetid, Null, 'Null', v_desc_tab(i).col_charsetid));

 INSERT INTO desc_col_test (col_id, col_desc) VALUES (i, 'col_charsetform:'||decode(v_desc_tab(i).col_charsetform, Null, 'Null', v_desc_tab(i).col_charsetform));

    end loop;

 
end;
/

SELECT *
FROM
  (SELECT col_id,
    regexp_substr(col_desc,'[^:]+',1,1) col_desc_name,
    regexp_substr(col_desc,'[^:]+',1,2) col_desc_value
  FROM desc_col_test
  ) pivot (MAX(col_desc_value) FOR col_desc_name IN ('col_name' AS COL_NAME, 'col_type' AS COL_TYPE, 'col_precision' AS COL_PRECISION,
  'col_max_len' AS COL_MAX_LEN, 'col_name_len' AS COL_NAME_LEN,
  'col_schema_name' AS COL_SCHEMA_NAME, 'col_schema_name_len' AS COL_SCHEMA_NAME_LEN,
  'col_scale' AS COL_SCALE, 'col_charsetid' AS COL_CHARSETID,
  'col_charsetform' AS COL_CHARSETFORM, 'Nullable' AS NULLABLE))
ORDER BY col_id;

Oracle Tricks: Getting a range of numbers

Another method for getting a range of dates from Oracle PL/SQL

select last_day(to_date(to_char(months.month) || '/1/' ||
                        to_char(years.year),
                        'mm/dd/yyyy')) as range_EOM
  from (select rownum year from dual connect by level <= 2019) years,
       (select rownum month from dual connect by level <= 12) months
 where years.year >= 2000
   and months.month >= 1

Grabbing UTC Hour from Oracle

A simple sql script for obtaining gmt hour from Oracle

select sys_extract_utc(systimestamp) as UTC,
extract(hour from sys_extract_utc(systimestamp) ) as UTC_HOUR,
extract(hour from cast(to_char(sysdate, 'DD-MON-YYYY HH24:MI:SS') as timestamp) ) as  local_hour
from dual

Generating a series of Previous Month End Dates for a given number of years in Oracle

A very short oracle query for generating a range of previous month end dates for a number of years

  with years as  
  (select extract(year from sysdate) - (level - 1) as year  
   from dual  
  connect by level <=  
    (select extract(year from sysdate) -  
        extract(year from date '2000-12-01')   --range of years sysdate to 2001 
     from dual)  
   order by year desc),  
 months as  
  (  
  select rownum as month_num,to_char(date '2000-12-01' + numtoyminterval(level,'month'),'MONTH') as month  
    from dual  
   connect by level <= 12  
 )  
 select last_day(to_date(to_char(years.year) || '-' ||   
 to_char(months.month_num) || '-1',  
         'yyyy-mm-dd')) as as_of_date  
  from years, months  
  where last_day(to_date(years.year || '-' || months.month, 'yyyy-mm')) < sysdate  

Full Year Pivot Using Oracle

A quick example of a full year pivot using Oracle

select 
  * 
FROM 
  (
    select 
      account_no, 
      to_char(
        trunc(some_date_column, 'MONTH'), 
        'MON YYYY'
      ) as transaction_month 
    from 
      some_table 
    where 
      trunc(some_date_column, 'YEAR') = '01-jan-2018'
  ) PIVOT (
    count(transaction_month) for transaction_month in (
      'JAN 2018', 'FEB 2018', 'MAR 2018', 
      'APR 2018', 'MAY 2018', 'JUN 2018', 
      'JUL 2018', 'AUG 2018', 'SEP 2018', 
      'OCT 2018', 'NOV 2018', 'DEC 2018'
    )
  )

Oracle Case statements when testing for NULL

Just a little tidbit when working with ORACLE and case statements.

The first method, where the given column name is passed to successive WHEN statements, WHEN must have a value to work with, so you have to convert the null value into something and test for it.

Method 1: Covert the incoming value first

CASE nvl(some_column,'NULL')
         WHEN 'NULL' THEN some_other_column
         WHEN 'ABC' THEN another_column
         ELSE
          some_column
         END some_column

Method 2: do the condition checks in the WHEN

CASE 
    WHEN nval(some_column,'NULL') = 'NULL' THEN some_other_column
     WHEN some_column = 'ABC' THEN another_column
     ELSE some_column
     END  some_column