Finding index and primary keys of tables

SELECT IFNULL(CONSTRAINT,'NUNIQUE'),
INDEX_NAME,COLUMN_NAME 
FROM INDEX_COLUMNS WHERE SCHEMA_NAME = '%s'
AND TABLE_NAME = '%s' 
ORDER BY INDEX_OID,POSITION

Show details of users that have been logged-in

select * from "SYS"."USERS"
where "LAST_SUCCESSFUL_CONNECT" is not null
order by 9 desc;

To get all Libraries

select to_char(definition) from public.libraries 
where schema_name='EXT';

To get all DDL

call get_object_definition('<SCHEMA>','<TABLENAME>');

ALTER TABLE schema.table ADD PRIMARY KEY (column1,column2)

Check invalid custom DB views

select * from "SYS"."VIEWS"
where schema_name not like 'SAP%' and is_valid = 'FALSE';

Check inactive custom DB objects

select * from "_SYS_REPO"."INACTIVE_OBJECT"
where "PACKAGE_ID" not like 'sap%';

Check which SAP language settings are being used by current user

select session_context('LOCALE_SAP'),
session_context('LOCALE') 
from dummy;

## Search executed SQL statements, 
e.g. to find out who deleted a table
select * from "SYS"."M_EXECUTED_STATEMENTS" 
where "STATEMENT_STRING" LIKE 'DROP TABLE%';

Show custom settings within global.ini and indexserver.ini

select * from "SYS"."M_INIFILE_CONTENTS"
where ("LAYER_NAME" = 'SYSTEM' or "HOST" <> ") 
and ("FILE_NAME" = 'global.ini' 
or "FILE_NAME" = 'indexserver.ini');

Show assigned user roles

select * from "SYS"."GRANTED_ROLES"
where "GRANTEE_TYPE" = 'USER';

Show assigned repository privileges

select * from "SYS"."GRANTED_PRIVILEGES"
where object_type = 'REPO';

Show objects owned by non-system users

select * from "SYS"."OWNERSHIP"
where owner_name not like 'SAP%' and owner_name not like '%SYS%'
order by 1,2;

Analyze expensive statement trace

select
to_varchar("STATEMENT_START_TIME",'DD.MM.YYYY') "EXEC_DATE",
to_varchar("STATEMENT_START_TIME",'HH24:MI:SS') "EXEC_TIME",
to_int("DURATION_MICROSEC"/1000000) "DURATION_S",
to_decimal("MEMORY_SIZE"/1073741824,10,1) "MEM_GB",
"RECORDS",
"DB_USER",
"APP_USER",
"APPLICATION_NAME",
"STATEMENT_STRING",
length("STATEMENT_STRING") "SQL_LENGTH",
OCCURRENCES_REGEXPR('JOIN' FLAG 'i' IN "STATEMENT_STRING") "JOIN",
OCCURRENCES_REGEXPR('CASE' FLAG 'i' IN "STATEMENT_STRING") "DISTINCT",
"ERROR_TEXT",
"PARAMETERS"
from "SYS"."M_EXPENSIVE_STATEMENTS"
where "OPERATION" in 
('INSERT','SELECT','AGGREGATED_EXECUTION') –exclude background activity
and "RECORDS" > 0
and to_varchar("STATEMENT_START_TIME", 'YYYYMMDD') = current_date
and to_int(to_varchar("STATEMENT_START_TIME",'HH24′)) 
between 8 and 17 –business hours
order by 3 desc;

Most Common Functions used in Implementation

SELECT SESSION_USER "session user" FROM DUMMY;

SELECT TO_DATE('2010-01-12', 'YYYY-MM-DD') "to date" 
FROM DUMMY;

SELECT TRIM ('a' FROM 'aaa123456789aa') "trim both" FROM DUMMY;

SELECT CURRENT_DATE "current date" FROM DUMMY;

SELECT 
DAYS_BETWEEN (TO_DATE ('2009-12-05', 'YYYY-MM-DD'),
TO_DATE('2010-01-05', 'YYYY-MM-DD')) "days between" 
FROM DUMMY;

SELECT UPPER ('Ant') "uppercase" 
FROM DUMMY;

SELECT CONCAT ('C', 'at') "concat" FROM DUMMY;

SELECT FLOOR (14.5) "floor" FROM DUMMY;

SELECT TO_DECIMAL(7654321.888888, 10, 3) "to decimal"
FROM DUMMY;

SELECT REPLACE ('DOWNGRADE DOWNWARD','DOWN', 'UP') "replace" 
FROM DUMMY;

SELECT RTRIM ('endabAabbabab','ab') "rtrim" FROM DUMMY;

SELECT RIGHT('HI0123456789', 20) "right" FROM DUMMY;

SELECT  WEEK ('2017-01-02') FROM DUMMY;

SELECT LENGTH ('length in char') "length" FROM DUMMY;

SELECT SUBSTRING ('1234567890',4,2) "substring" FROM DUMMY;

SELECT WEEKDAY (TO_DATE ('2010-12-31', 'YYYY-MM-DD')) "week day" 
FROM DUMMY;

SELECT TO_VARCHAR (TO_DATE('2009-12-31'), 'YYYY/MM/DD') "to varchar" 
FROM DUMMY;

SELECT 
YEARS_BETWEEN(TO_DATE('2001-01-01'), 
TO_DATE('2003-03-14')) "years_between" 
FROM DUMMY;

SELECT YEAR (TO_DATE ('2011-05-30', 'YYYY-MM-DD')) "year" 
FROM DUMMY;

SELECT MONTH ('2011-05-30') "month" FROM DUMMY;

SELECT NOW () "now" FROM DUMMY;

SELECT LAST_DAY (TO_DATE('2010-01-04', 'YYYY-MM-DD')) "last day" FROM DUMMY;


SET SCHEMA "SAPABC";
 CREATE TABLE MY_DATES (FCID NVARCHAR(2), STARTDATE DATE, ENDDATE DATE);
 INSERT INTO MY_DATES VALUES ('01', '2014-01-01', '2014-02-14');
 INSERT INTO MY_DATES VALUES ('01', '2014-04-01', '2014-05-14');
 INSERT INTO MY_DATES VALUES ('01', '2014-07-01', '2014-08-05');
 INSERT INTO MY_DATES VALUES ('01', '2014-10-01', '2014-10-30');
 SELECT WORKDAYS_BETWEEN(FCID, STARTDATE, ENDDATE) "production duration" FROM MY_DATES;

Keep watching here and comment if you like to add on top of it