C170 WGU ALREADY PASSED
DML - ✔✔IUDS, CR
insert, update, delete, select
commit, rollback
INSERT - ✔✔add new rows
UPDATE - ✔✔modify data of existing rows
DELETE - ✔✔delete some/all records from database
can be rolled back
COMMIT - ✔✔permanently saves
ROLLBACK - ✔✔undo changes
SELECT - ✔✔data retrieval
WHERE - ✔✔limits rows returned
used before group by
ORDER BY - ✔✔OC
sorts columns
, GROUP BY - ✔✔GR
groups rows
BETWEEN - ✔✔within range
IS NULL - ✔✔value is null
LIKE - ✔✔value matches string pattern
IN - ✔✔checks value if it matches given value list
EXISTS - ✔✔checks if subquery returns any rows
COUNT - ✔✔tally amount of NON-NULL values
SUM - ✔✔total sum for specified attribute
HAVING - ✔✔filters the groups subject to some condition
used after group by
inner join - ✔✔only rows that meet criteria selected
outer join - ✔✔matching rows and unmatched values for one/both tables
natural join - ✔✔returns ALL rows with matching values
deletes duplicate columns
DML - ✔✔IUDS, CR
insert, update, delete, select
commit, rollback
INSERT - ✔✔add new rows
UPDATE - ✔✔modify data of existing rows
DELETE - ✔✔delete some/all records from database
can be rolled back
COMMIT - ✔✔permanently saves
ROLLBACK - ✔✔undo changes
SELECT - ✔✔data retrieval
WHERE - ✔✔limits rows returned
used before group by
ORDER BY - ✔✔OC
sorts columns
, GROUP BY - ✔✔GR
groups rows
BETWEEN - ✔✔within range
IS NULL - ✔✔value is null
LIKE - ✔✔value matches string pattern
IN - ✔✔checks value if it matches given value list
EXISTS - ✔✔checks if subquery returns any rows
COUNT - ✔✔tally amount of NON-NULL values
SUM - ✔✔total sum for specified attribute
HAVING - ✔✔filters the groups subject to some condition
used after group by
inner join - ✔✔only rows that meet criteria selected
outer join - ✔✔matching rows and unmatched values for one/both tables
natural join - ✔✔returns ALL rows with matching values
deletes duplicate columns
