Right Join

Every rows from right table and matching records from left

select
emp.id,
emp.name,
dept.name
from employee emp
right join department dept
on emp.dept_id = dept.dept_id

Even if the department doesn't have employees, it will be listed. If an employee doesn't have a department, it will not be listed.

Left Join

Every rows from left table and matching records from right

select
emp.id,
emp.name,
dept.name
from employee emp
left join department dept
on emp.dept_id = dept.dept_id

Even if the employee doesn't have a department, he/she will be listed here.

Replace

SELECT oreplace('Hello There','Hello','Hi')

This converts Hello There to Hi There.

Teradata: Extract month and year from date

 extract (year from date1)

 extract (month from date1)

Teradata: Backup table with data

create table table1_bkup as
table1 with data

Teradata: List columns of a table

select
*
from dbc.columns
where tablename ='table1'
and databasename = 'database1'

Teradata: List tables in database

select
*
from dbc.tables
where databasename='database'
and tablekind = 'T'

Teradata: Add column with default value

alter table table1 add col1 int default 0

Teradata: Rename table

rename table table1 to table2

Teradata: Add column

alter table table1 add x int;

Teradata SQL: Drop column

alter table table1 drop col1

Teradata SQL: Update column name

alter table table1 rename col1 to col1_updated

Teradata SQL: Create table using Select statement

Execute following 2 SQLs:

1. create table tablex as
(
select
a,
b,
c
from table1
)
with no data;

2. insert into tablex
select
a,
b,
c
from table1;

Teradata recursive sql

Suppose we have a table:
create table accont_tbl
acct_id int,
manager_acct_id int,
name varchar(50)
)
which contains employee records with their supervisor.

Then the recursive sql is:
with recursive mgr_tbl(acct_id, manager_acct_id, mgr_name, depth) as
(
select
a.acct_id,
a.manager_acct_id,
a1.name as mgr_upn,
1 as depth
from account_tbl a
inner join account_tbl a1
on a.manager_acct_id = a1.acct_id
where a.acct_id = 8976
union all
select
mgr_tbl.acct_id,
a.manager_acct_id,
a1.name,
mgr_tbl.depth+1
from mgr_tbl
inner join account_tbl a
on mgr_tbl.manager_acct_id = a.acct_id
inner join account_tbl a1
on a.manager_acct_id = a1.acct_id
-- where mgr_tbl.mgr_upn <> 'email of root if root's manager is same as accout'
)
select * from mgr_tbl order by depth

Regular expression to remove blank lines

If you are using Notepad++, replace ^[\n\r]+ with nothing in the replace

Regular expression to remove html and get only values from a select list

Regular expression : ^<.*>

Replace ^<.*> with blank if we use Notepad++

Example:
<option value="/html/A.htm">A
<option value="/html/B.com">B
<option value="/html/C.htm">C

The replace will produce:
A
B
C

Teradata sql - retrieve top and bottom 50 percentage of the records

Top 50%
----------
select top 50 percent  *
from table1
order by id asc

Bottom 50%
---------------
select top 50 percent  *
from table1
order by id desc

Update from select

Update table1
from
(
select
t1.x,
t1.y
from table2 t2
left join table3 t3
on t2.id = t3.id
) input
set f1 = input.x
where f2 = input.y

Insert into with select

Insert into table1
(
field1,
field2,
field3
)
select
t2.x,
t2.y,
t3.x
from table2 t2
left join table3 t3
on t2.id = t3.id

Remove carriage returns from a field

select oTranslate(afield, '0A0D'xc,' ') from atable