1. OLTP
Will be talking about On Line Transaction Processing OLTP for most of this course
Operational databases
As opposed to OLAP On Line Analytical Processing
Decision support

2. SQL Chapters 6, 7

3. SQL or SEQUEL (Structured English Query Language)
Based on relational algebra
First called ‘Square’
Developed in 1970's released in early 1980's
Standardized - SQL-92 (SQL2), SQL-3, SQL:1999 (SQL-99), 2003 (aka SQL: 200n), SQL:2008
SQL:2011
2011 includes better support for temporal databases
SQL: 2016
access JSON

4. SQL
High-level DB language used in ORACLE, etc. created at IBM with System R
 SQL provides DDL and DML  
DDL - create table, drop table, alter table
DML - Queries in SQL

5. SQL
Is SQL useful?
Languages to learn

6. Give examples of queries in English
What basic keywords would you use for a query language for a DB

7. SQL Basic building block of SQL is the Select Statement
SELECT <attribute list>
FROM <table list >
[WHERE <search conditions>]

8. Select Statement
Select - chooses columns (project operation p in relational algebra)
From - combines tables if > 1 table (join operation |X| in relational algebra and Cartesian product X)
Where - chooses rows (select operation s in relational algebra)
Result of a query is usually considered another relation
Results may contain duplicate tuples

9. Queries Select specified columns for all rows of a table
Select all columns for some of the rows of a table
Select specified columns for some rows of a table
Select all rows and columns of a table
All of the above for multiple tables

10. select lname from employee LNAME ---------- Smith Wong Zelaya Wallace Narayan English Jabbar Borg

11. select salary from employee; SALARY ---------- 30000 40000 25000 43000 38000 55000

12. Differences with relational model
Relation not a set of tuples - a multiset or bag of tuples
Therefore, 2 or more tuples may be identical
Use distinct to eliminate duplicate tuple
Select distinct salary from employee

13. Select Clause Select <attribute list> Attribute list can be:
Column names
* lists all attributes in a table
Constants
arithmetic expressions involving columns, etc.
Aggregate functions
In Oracle, can also be a select statement (but select can only return 1 column and 1 row)
To rename an attribute, keyword ‘as’ is optional
Select lname as last_name
From employee

14. Queries
To retrieve all the attribute values of the selected tuples, a * is used:
Select *
From Employee

15. From clause From <table list> Table list can be:
one or more table names
a select statement itself

16. Where clause Where <search conditions>
You can specify more than one condition in the where clause separated by:
and or

17. Where clause Where <search conditions> (s in relational algebra)
Search conditions can be:
Comparison predicate: expr § expr2
where § is <, >, <=, etc.
in, between, like, is, etc.
expr is constant, col, qual.col, aexpr op aexpr
expr2 is expr | select statement
expr can be a select statement
expr CANNOT be an aggregate – must appear within a select statement

18. Retrieve the ssn of the employee whose name is 'Smith‘
SQL> select ssn
2 from employee
3 where lname='Smith';
SSN

19. Miscellaneous SQL is NOT case sensitive
Select from employee
select FROM EMPLOYEE
Except when comparing character strings
All character strings in SQL are surrounded by single quotes
where lname='Smith'
However, tables names in some RDMS (MySQL) are case sensitive

20. Our Oracle Server We have an Oracle Server set up for this class:
Our server is: vrbsky-oracle.ua-net.ua.edu
In order to access this server you need Oracle client software installed on your laptop. One possibility is:
SQL developer from the Oracle website
NOTE: to download SQL developer you may need to create an account for the Oracle website. This is NOT the same as your Oracle Server login/pw

21.
Create your own account for
Download SQL Developer
Oracle Client software
Oracle Server
Located at
UA in OIT
Use login/PW given to connect to
our local Oracle Server
vrbsky-oracle.ua-net.ua.edu
Using SQL Developer:
Create DB tables – commands given
Start running SQL queries

22. Once you have installed the Oracle client you need to tell it where to find the server and your login/pw
Your Oracle Server username is your bama id
Your Password is your CWID
Info about setting up the Oracle client

23. If you need to delete a table:
Once you can connect to our Oracle Server you should create the Company DB –
Create the Company DB by cutting/pasting these SQL statements in your Oracle client.
If you need to delete a table:
Drop table table_name;

24. SQL query
Oracle
Server
Query result
vrbsky-oracle.ua-net.ua.edu

25. What if you want a list of the employee SSNs and department number of the departments they work for?
Select SSN, dno
From Employee
What if you want a list of the employee SSNs and name of the departments they work for?

26. Combining tuples using where clause
To retrieve data that is in more than one table can use:
a cartesian product X
List ssn and dname of department employee works for Select ssn, dname
From Employee, Department
A join operation |X|
Select ssn, dname
Where dno=dnumber               

27. Combining tuples in from clause
A cartesian product combines each tuple in one table, with all the tuples in the second table (and all columns unless specified in select clause)
A join combines a tuple from the first table with tuple(s) in the second table if the specified (join) condition is satisfied (again, all columns included unless specified in select clause)
This join is also referred to as an inner join

28. Alternative SQL notation for Join
Select ssn, dname From Employee Join Department on dno=dnumber Select lname, relationship From Employee Join Dependent on ssn=essn Where dno=5

29. Select * From Employee, Dependent

30. Where clause Select ssn, fname, lname From Employee Join
From Employee, Department
Where mgrssn=ssn and sex='F'
Mgrssn=ssn is a join condition
Sex=‘F’ if a select condition
Select ssn, fname, lname
From Employee Join
Department on dno=dnumber
Where dname=‘Research’

31. Additional characteristics
In SQL we can use the same name for 2 or more attributes in different relations. Must qualify the attributes names:
employee.lname
department.*

32. Additional characteristics
Aliases are used to rename relations
List dname of each department and its locations
Select dname as dept_name, dlocation
From Department D, Dept_Locations DL
Where DL.dnumber = D.dnumber
NOTE: cannot use ‘as’ keyword here in Oracle

33. Predicates
Predicates evaluate to either T or F. Many of the previous queries can be specified in an alternative form using nesting.

34. In predicate
The in predicate tests set membership for a single value at a time.
In predicate: expr [not] in (select | val {, val})
Select <attribute list> From <table list>
Where expr in (select | val {, val})

35. In predicate
Select SSN of employees who work in departments located in Houston
The outer query selects an Employee tuple if its dno value is in the result of the nested query.
Select SSN of employees who do not work in departments located in Houston

36. Quantified predicate
Quantified predicate compares a single value with a set according to the predicate.
Quantified predicate: expr § [all | any] (select)
Select <attribute list> From <table list>
Where expr § [all | any] (select)
§ is < > = <> <= >=

37. Quantified predicate Write using quantified predicate:
Select SSN of employees who work in departments located in Houston
Which predicate should be used?
= all, = any, > all, etc.?

38. Quantified predicate What does the following query? Select *
From Employee
Where salary > all (Select salary
Where sex = 'F')
= any equivalent to in
not in equivalent to <> all or != all

39. Exists predicate
The exists predicate tests if a set of rows is non-empty
Exists predicate: [not] exists (select)
Select <attribute list> From <table list>
Where exists (select)

40. Exists predicate
Exists is used to check whether the result of the inner query is empty or not. If the result is NOT empty, then the tuple in the outer query is in the result.

41. Exists predicate Write using exists predicate:
Select SSN of employees who work in departments located in Houston

42. Exists predicate
Exists is used to check whether the result of the inner query is empty or not. If the result is NOT empty, then the tuple in the outer query is in the result.
Exists is used to implement difference (‘not in’ also used) and intersection.

43. Exists predicate
Retrieve all the names of employees who do not work in a department located in Houston.
Retrieves the locations of the department Employee works for to see if one of them is Houston. If none exist (the inner query is empty and not exists is true) the Employee tuple is in the result.

44. select ssn from employee, dept_locations where dno=dnumber and dlocation=‘Houston’; Select ssn from employee join dept_locations on dno=dnumber Where dlocation=‘Houston’; select ssn from employee where dno in (select dnumber from dept_locations where dlocation='Houston'); where dno =any (select dnumber from dept_locations where exists (select dnumber from dept_locations where dlocation='Houston' and dno=dnumber);

45. SSN of employees who work for department located in Houston
select ssn from employee, dept_locations where dno=dnumber and dlocation=‘Houston’; Select ssn from employee join dept_locations on dno=dnumber Where dlocation=‘Houston’; select ssn from employee where dno in (select dnumber from dept_locations where dlocation='Houston'); where dno =any (select dnumber from dept_locations where exists (select dnumber from dept_locations where dlocation='Houston' and dno=dnumber);

46. Note: if the query asks for the Research department you MUST use ‘Research’ in your query NOT dno=5
Why??

47. Correlated Nested Queries
If a condition in the where-clause of a nested query references an attribute of a relation declared in an outer query, the two queries are said to be correlated.
The result of a correlated nested query is different for each tuple (or combination of tuples) of the relation in the outer query.
Which takes longer to execute? a correlated nested query or a non-correlated nested query?

48. Join Conditions
For every project located in 'Stafford' list the project number, the controlling department number and department manager's last name, address and birthdate.   
How many join conditions in the above query?
How many selection conditions?

49. Write queries to do the following:
List the pno of the project and essn of employees who work more than 20 hours on a project
List the pname of the project and essn of employees who work more than 20 hours on a project
Optional – for fun: Using one of the predicates
List the fname, lname of employees who have a
dependent.
screenshot to
Include HW#1 CS301 and Section 1 in the subject

50. Note: if the query asks for the Research department you MUST use ‘Research’ in your query NOT dno=5
Why??

51. Join queries queries
List the pname of projects and dname of their departments.
List the name of employees who have dependents with the same birthday as they do.

52. Join Queries List all employee names and their supervisor names
select e.lname, s.lname
from employee e, employee s
where e.superssn=s.ssn;

53. Single block queries
An Expression written using =any or IN may almost always be expressed as a single block query.
Find example where this is not true in your textbook

54. List All Employees and the name of any department if they manage one
List All Employees and the name of any department if they manage one. If they don’t manage any department they should still be included.

55. Outer Join Outer Join - extension of join and union
In a regular join, tuples in R1 or R2 that do not have matching tuples in the other relation do not appear in the result.
Some queries require all tuples in R1 (or R2 or both) to appear in the result
When no matching tuples are found, nulls are placed for the missing attributes.

56. Outer Join
You can use the keywords left, right, full (works in Oracle)
The following is a left outer join
Select lname, dname
From Employee Left Outer Join
Department on ssn=mgrssn
The keyword Outer is optional

57. LNAME DNAME
Wong Research
Wallace Administration
Borg Headquarters
Jabbar
English
Zelaya
Narayan
Smith

58. Outer Join You can also use a + to indicate an outer join
The following example indicates a left outer join in Oracle
Select lname, dname
From Employee, Department
Where ssn=mgrssn(+)
     Select lname, dname         From Employee Left Outer Join Department on ssn=mgrssn

59. Nested queries
In general we can have several levels of nested queries.
An inner query can reference an attribute in an outer query
An outer query cannot reference an attribute in an inner query (like scope rules in higher level languages).
A reference to an unqualified attribute refers to the relation declared in the inner most nested query.
A reference to an attribute must be qualified if its name is ambiguous. 

60. Will this work? Select ssn, dname from employee
Suppose you want the ssn and dname of each employee not in the Research department:
Select ssn, dname
from employee
where dno not in (select dnumber from department
where dname='Research')

61. Nested select statements
Select lname, dno
From employee
Where dno = (select dnumber from department
where dname = 'Research');
You need to be careful using this. Result must be a single value
Where dno = (select dnumber from dept_locations
where dlocation= 'Houston');

62. More SQL
Anything missing to answer typical queries?

63. Aggregate functions Aggregate Functions (set functions, aggregates):
Include COUNT, SUM, MAX, MIN and AVG
aggr (col)
Find the maximum salary, the minimum salary and the average salary among all employees.
Select MAX(salary), MIN(salary), AVG(salary)
From Employee

64. Aggregates Retrieve the total number of employees in the company
Select COUNT(*)
From Employee
Retrieve the number of employees in the research department.
From Employee, Department
Where dno=dnumber and dname='Research'

65. Aggregates Note that: Select COUNT(*)
from Employee
Will give you the same result as:
Select COUNT(salary) from Employee
Unless there are nulls - not counted
To count the number of distinct salaries.
Select COUNT(distinct salary)
From Employee

66. Aggregates Additional aggregates have been added to RDBMS - variance
Read the Oracle documentation to see what has been added

67. List average salary, max salary over all employees
List lname, salary for employees with salaries > average salary
List lname, salary for employees with salaries > average salary for their department

68. SELECT dno, lname, salary
FROM employee e
WHERE salary >
(SELECT AVG(salary)
FROM employee
WHERE e.dno=dno);
What if we get rid of the ‘e’ in e.dno?

69. List each department name and average salary
Difficult to write?

70. Grouping
We can apply the aggregate functions to subgroups of tuples in a relation.
Each subgroup of tuples consists of the set of tuples that have the same value for the grouping attribute(s).
The aggregate is applied to each subgroup independently.
SQL has a group-by clause for specifying the grouping attributes.
Group By col {, col}

71. Grouping
For each department, retrieve department name, the average salary
Select dname, AVG(salary)
From Employee, department
where dno=dnumber
Group By dname
The tables are joined
The tuples are divided into groups with the same dname
AVG are then applied to each group.

72. Oracle group by – STANDARD SQL
Only grouping attribute(s) and aggregate functions can be listed in the SELECT clause.
Expressions in the GROUP BY clause can contain any columns of the tables or views in the FROM clause, regardless of whether the columns appear in the SELECT clause.
Some DBMS (e.g. MySQL) do not implement standard SQL
In this class everyone will use standard SQL

73. For each department, retrieve the department number, department name, the average salary and total number of employees. Select dno, dname, AVG(salary), count(*) From Employee, department where dno=dnumber Group By dno, dname

74. List each department name and average salary
We will try writing it without group by later

75. Write the following SQL queries:
list employee name, their department name and number, and salary for employees with salary > $32,000.
list department name, department number and average salary

76. 3. What if you want those departments with average salary > 32000?

77. Having Clause
Sometimes we want to retrieve those tuples with certain values for the aggregates (Group By).
The having clause is used to specify a selection condition on a group (rather than individual tuples).
If a having is specified, you must specify a group by.
Having search_condition

78. With group by / Having List departments with average salary > 32000
select dname, avg(salary)
from department, employee
where dno=dnumber
group by dname
having avg(salary) > 32000;

79. Which departments have an avg salary > than the overall avg salary?
select dname, avg(salary)
from department, employee
where dno=dnumber
group by dname
having avg(salary) > (select avg(salary)
From employee);

80. Subselect formal definition
Select called Subselect
Select expr {, expr}
From tablename [alias] {, tablename [alias]}
[Where search_condition]
[Group By col {, col}]
[Having search_condition]

81. Select Select is really:
Subselect {Set_Operation [all] Subselect}  [Order By col [asc | desc] {, col [asc | desc]}]

82. Order By
To sort the tuples in a query result based on the values of some attribute:
Order by col_list
Default is ascending order (asc), but can specify descending order (desc)

83. Order by
Retrieve names of the employees, their department, and salary and order it by department and within each department order the employees salary in descending order.
Select lname, fname, dname, salary
From department, employee
Where dno=dnumber
Order by dname, salary desc

84. Set Operations The Set Operations are: UNION, INTERSECT and MINUS
NOTE: MySQL does not have minus
The resulting relations are sets of tuples; duplicate tuples are eliminated.
Operations apply only to union compatible relations. The two relations must have the same number of attributes and the attributes must be of the same type.

85. Union
SELECT bdate
FROM employee
UNION
FROM dependent

86. List essn of employee who work on both pno=1 and pno=2
Select essn from works_on where pno=1
Intersect
Select essn from works_on where pno=2

87. Set operations - Intersect
List all project names for projects that are worked on by an employee whose last name is Smith and has Wong as a manager of the department that controls the project
(Select pname
From Project, Works_on, Employee
Where pnumber=pno and essn=ssn and lname='Smith')
Intersect
(Select pname
From Project, Department, Employee
Where dnum=dnumber and mgrssn=ssn and lname='Wong')

88. Minus
Example using minus: Select departments that are not located in ‘Houston’ We wrote using ‘in’ predicate: Select dnumber from dept_locations where dnumber not in ( Select dnumber from dept_Locations Where dlocation = 'Houston'); Now use minus: Select dnumber from department Minus Where dlocation = 'Houston';

89. Minus Select departments that are not located in ‘Houston’
Without minus or ‘in’ – does this work?
Select dnumber from dept_locations
Where dlocation <> 'Houston';

90. 1:1, 1:N, N:M relationships Select employees who do not work for dno=4
Select dno of departments that doesn’t have ssn= as an employee (e.g. ssn= doesn’t work for that department)
Select * from employee //N side of 1:N
Where dno<>4;
Select dno from employee //1 side of 1:N – NOT correct
Where ssn<> ;
//Correct
select dno from employee
minus
where ssn = ;

91. The difference is:
1:N (on the N-side) or 1:1 //can use <>
versus
1:N (on the 1-side) or N:M //cannot use <>
What are all the 1:1, 1:N, N:M relationships in the Company DB?

92. Example Compute the average number of employees over all departments
There are several ways to do this, but note that you can do:
aggr(aggr(col))
But you will need a group by somewhere in your query
select avg(count(essn))
from dependent,employee
where ssn=essn(+)
group by ssn;

93. Earlier we considered
List each department name and average salary
Now try writing it without group by

94. Try to nest select in select clause
select dname, (select avg(salary) as avgsal from employee where dno=dnumber)
from department;

95. Grouping Without the having:
list department name, average salary for departments with average salary > $32,000.
Will this work?
Select dname, avg(salary)
From department, employee
Where dno=dnumber and avg(salary) > 32000
Group by dname;

96. //instead these work select dname, avg(salary) from department, employee where dno=dnumber and (select avg(salary) from employee where dno=dnumber) > group by dname; //try to write it using a nested query in the from clause

97. select dname, avgsal
from (select dno, avg(salary) as avgsal from employee group by dno), department
where dno=dnumber and avgsal > 32000

98. Try to nest select in select clause
//Does NOT work!! - can't recognize avgsal if inside () or outside ()
But it can be written without group by or having
select dname, (select avg(salary) as avgsal from employee where dno=dnumber)
from department
where avgsal > 32000;

99. Listed as extra credit in homework

100. Queries Using the student and dept tables
Student( ID, Age, GPA, Major)
Dept(Name, DeptHead, Location, College)
Using the student and dept tables
List the dept name and number of majors
Assume some departments may not have any majors:

101. Example - Queries Compute the number of dependents
List the essn and number of dependents for employee with dependents
List the essn and number of dependents for employees with or without dependents
Compute the average number of dependents over employees with dependents
select avg(count(essn))
from dependent,employee
where ssn=essn(+)
group by ssn;

102. How do we count over all employees?
SQL> select count(*)
2 from employee, dependent
3 where ssn=essn
4 group by essn;
COUNT(*) 3 1
SQL> select essn, count(*)
2 from employee, dependent
3 where ssn=essn
4 group by essn;
ESSN COUNT(*)
How do we count over all employees?
SQL> select avg(count(*))
2 from employee, dependent
3 where ssn=essn
4 group by essn;
AVG(COUNT(*))
SQL> select avg(cnt)
2 from (select count(*) as cnt
3 from employee, dependent
4 where ssn=essn group by essn);
AVG(CNT)
select avg(select count(*)
from employee, dependent
where ssn=essn group by essn)
from employee;
Gives an error

103. DDL – Data Definition in SQL
Used to CREATE, DROP and ALTER the descriptions of the relations of a database
CREATE TABLE
Specifies a new base relation by giving it a name, and specifying each of its attributes and their data types
CREATE TABLE name (col1 datatype, col2 datatype, ..)

104. Data Types Data types: (ANSI SQL vs. Oracle)
There are differences between SQL and Oracle, but Oracle will convert the SQL types to its own internal types
int, smallint, integer converted to NUMBER
Can specify the precision and scale
Float and real converted to number
Character is char(l) or varchar2(l), varchar(l) still works
Have date, blob, etc.

105. Constraints
Constraints are used to specify primary keys, referential integrity constraints, etc.
[CONSTRAINT constr_name] PRIMARY KEY
need to name it if want to alter it later
CONSTRAINT constr_name REFERENCES
table (col)
The table(col) referenced must exist
Constraint names must be unique across database
You can also specify NOT NULL for a column
You can also specify UNIQUE for a column

106. Create table – In line constraint definition
Create table Project1 (pname varchar2(9)
CONSTRAINT pk PRIMARY KEY,
pnumber int not null,
plocation varchar2(15),
dnum int CONSTRAINT fk
REFERENCES Department (dnumber),
phead int);

107. Create table
To create a table with a composite primary key must use out of line definition:
Create table Works_on (essn char(9), pno
int, hours number(4,1),
PRIMARY KEY (essn, pno));

108. Oracle Specifics
A foreign key may also have more than one column so you need to specify an out of line definition
There are differences with the in line
When you specify a foreign key constraint out of line, you must specify the FOREIGN KEY keywords and one or more columns.
When you specify a foreign key constraint inline, you need only the REFERENCES clause.

109. Create table – out of line constraint definition
Create table Project2 (pname varchar2(9),
pnumber int not null,
plocation varchar(15),
dnum int, phead int,
PRIMARY KEY (pname),
CONSTRAINT fk FOREIGN KEY (dnum)
REFERENCES Department (dnumber));

110. DROP TABLE Used to remove a relation and its definition
The relation can no longer be used in queries, updates or any other commands since its description no longer exists
Drop table dependent;

111. ALTER TABLE To alter the definition of a table in the following ways:
to add a column
to add an integrity constraint
to redefine a column (datatype, size, default value) – there are some limits to this
to enable, disable or drop an integrity constraint or trigger
other changes relate to storage, etc.

112. Alter table - Oracle
The table you modify must have been created by you, or you must have the ALTER privilege on the table.
If used to add an attribute to one of the base relations, the new attribute will have NULLS in all the tuples of the relation after command is executed; hence, NOT NULL constraint is not allowed for such an attribute.
Alter table employee add job varchar(12);
The database users must still enter a value for the new attribute job for each employee tuple using the update command. Oracle alter

113. How to create a table when?
CONSTRAINT constr_name REFERENCES
table (col)
The table(col) referenced must exist
Department mgrssn references employee ssn with mgrssn
Employee dno references department dnumber

114. Alter is useful when … You have two tables that reference each other
Table must be defined before referenced, so how to define?:
department mgrssn references employee ssn with mgrssn
Employee dno references department dnumber
Create employee table without referential constraint for dno then
Create department table with reference to mgrssn
Alter employee and add dno referential constraint
Or when you specify create table you can disable the references, then enable them later

115. Updates (DML) Insert, delete and update INSERT
Insert into table_name ( [(col1 {, colj})] values (val1 {, valj}) | (col1 {, colj}) subselect )
add a single tuple
attribute values must be in the same order as the CREATE table

116. Insert
Insert into Employee values ('Richard', 'K', 'Marini', ' ', '30-DEC-52', '98 Oak Forest, Katy, TX', 'M', 37000, ' , 4);
Use null for null values in ORACLE

117. Insert
Alternative form - specify attributes and leave out the attributes that are null
Insert into Employee (fname, lname, ssn) values ('Richard', 'Marini', ' ');
Constraints specified in DDL are enforced when updates are applied.

118. Insert To insert multiple tuples from existing table:
create table ename (name varchar(15));
Table created.
insert into ename (select lname from employee);
8 rows created.
select * from ename;
NAME
Smith
Wong
Zelaya
Wallace
Narayan
English
Jabbar
Borg

119. Importing Data
Obviously there are many utilities to import large amounts of data
In Oracle SQL developer, use Tools -> Preferences->Databse-> Utilities-> Import
Then set File Formats

120. Delete Delete from table_name [search_condition]
If include a where clause to select, tuples are deleted from table one at a time
The number of tuples deleted depends on the where clause
If no where clause included all tuples are deleted - the table is empty

121. Delete Examples: Delete From Employee Where dno = 5;
Where ssn = ' ‘;
Delete from Employee
Where dno in (Select dnumber
From Department
Where dname = 'Research');
Delete from Employee;

122. Update Modifies values of one or more tuples
Where clause used to select tuples
Set clause specified the attribute and value (new)
Only modifies tuples in one relation at a time
Update <table name>
Set attribute = value {, attribute = value}
Where <search conditions>

123. Update Examples: Update Project Set plocation = 'Bellaire', dnum = 5
Where pnumber = 10
Update Employee
Set salary = salary * 1.5
Where dno = (Select dnumber
From department
Where dname = ‘Headquarters')

124. Metadata To get information about a specific table: Describe employee
Lists all attributes and type
To get information about all user tables, can query user_tables
Select table_name from user_tables

125. System tables user_tables user_tab_columns user_constraints
user_cons_columns
user_triggers
user_views
user_tab_privs
user_tab_privs_made (lists privileges granted to others)
user_col_privs

126. Standard SQL What is the deal with MySQL vs. standard SQL?
Oracle has standard SQL
MySQL does not

127. Example Queries
Suppose you have created a table QtrSales (ID, Q1, Q2, Q3, Q4)
SQL to compute the total sales for each quarter?
SQL to compute the total sales for each ID?