Introduction to Oracle - SQL

Additional information is available in speaker notes!

IDNO NAME STADR CITY ST ZIP DATEFST YRGOAL CONTACT----- --------------- --------------- ---------- -- ----- --------- --------- ------------11111 Stephen Daniels 123 Elm St Seekonk MA 02345 03-JUL-98 500 John Smith12121 Jennifer Ames 24 Benefit St Providence RI 02045 24-MAY-97 400 Susan Jones22222 Carl Hersey 24 Benefit St Providence RI 02045 03-JAN-98 Susan Jones23456 Susan Ash 21 Main St Fall River MA 02720 04-MAR-92 100 Amy Costa33333 Nancy Taylor 26 Oak St Fall River MA 02720 04-MAR-92 50 John Adams34567 Robert Brooks 36 Pine St Fall River MA 02720 04-APR-98 50 Amy Costa

Donor tableDonor table

The donor table contains 8 fields or columns: IDNO, NAME, STADR, CITY, STATE, ZIP, DATEFST, YRGOAL and CONTACT. Note: the names of the fields/columns in the header below refers to STATE as ST since the column is small and the entire name will not fit over the column.

We will cover creating tables in the next presentation.

Donor tableDonor table The SELECT command is used to obtain information from a table. The listing of information on the previous slide and below used the SELECT. SELECT is one of the major commands used in working with SQL. There are many clauses that accompany the SELECT that allow the developer to obtain a wide variety of information.

IDNO NAME STADR CITY ST ZIP DATEFST YRGOAL CONTACT----- --------------- --------------- ---------- -- ----- --------- --------- ------------11111 Stephen Daniels 123 Elm St Seekonk MA 02345 03-JUL-98 500 John Smith12121 Jennifer Ames 24 Benefit St Providence RI 02045 24-MAY-97 400 Susan Jones22222 Carl Hersey 24 Benefit St Providence RI 02045 03-JAN-98 Susan Jones23456 Susan Ash 21 Main St Fall River MA 02720 04-MAR-92 100 Amy Costa33333 Nancy Taylor 26 Oak St Fall River MA 02720 04-MAR-92 50 John Adams34567 Robert Brooks 36 Pine St Fall River MA 02720 04-APR-98 50 Amy Costa

FORMAT:FORMAT:

SELECT {columns)FROM {table};

SQL> SELECT * 2 FROM donor;

The SELECT statement below was issued in Oracle at the SQL prompt.

SELECT * means select all columns.

The FROM clause specifies that the donor table should be used.

The results will be the listing of all columns for all records/rows in the donor table. The results are shown below.

IDNO NAME STADR CITY ST ZIP DATEFST YRGOAL CONTACT----- --------------- --------------- ---------- -- ----- --------- --------- ------------11111 Stephen Daniels 123 Elm St Seekonk MA 02345 03-JUL-98 500 John Smith12121 Jennifer Ames 24 Benefit St Providence RI 02045 24-MAY-97 400 Susan Jones22222 Carl Hersey 24 Benefit St Providence RI 02045 03-JAN-98 Susan Jones23456 Susan Ash 21 Main St Fall River MA 02720 04-MAR-92 100 Amy Costa33333 Nancy Taylor 26 Oak St Fall River MA 02720 04-MAR-92 50 John Adams34567 Robert Brooks 36 Pine St Fall River MA 02720 04-APR-98 50 Amy Costa

Donor tableDonor table

To select only certain fields/columns, the user would write the column names after the SELECT. The order that they are written determines the order of display.

SQL> SELECT state, name, datefst 2 FROM donor;

ST NAME DATEFST-- --------------- ---------MA Stephen Daniels 03-JUL-98RI Jennifer Ames 24-MAY-97RI Carl Hersey 03-JAN-98MA Susan Ash 04-MAR-92MA Nancy Taylor 04-MAR-92MA Robert Brooks 04-APR-98

6 rows selected.

SQL>

SELECT state, name, datefstFROM donor;

SQL prompt.

Donor tableDonor table

When the columns are show, numeric data is justified right and date and character data are justified to the left. In this table, IDNO is character, NAME is character, YRGOAL is numeric and DATEFST is date. Notice that YRGOAL is justified right, while IDNO, NAME and DATEFST are justified left..

SQL> SELECT idno, name, yrgoal, datefst 2 FROM donor;

IDNO NAME YRGOAL DATEFST----- --------------- --------- ---------11111 Stephen Daniels 500 03-JUL-9812121 Jennifer Ames 400 24-MAY-9722222 Carl Hersey 03-JAN-9823456 Susan Ash 100 04-MAR-9233333 Nancy Taylor 50 04-MAR-9234567 Robert Brooks 50 04-APR-98

6 rows selected.

SQL>

Donor tableDonor table

A column alias may be used by the developer. The alias will show up as the header, it will not effect the name of the data.

If the alias is two words or a change it case, it must be enclosed in quotes.

Note that the comma is used between field/column names, there is no comma between the field name and the column alias.

Note also the optional word AS between column name and column alias as shown below.

SQL> SELECT idno "ID #", name "Donor Name", datefst as "1st Gave" 2 FROM donor;

ID # Donor Name 1st Gave----- --------------- ---------11111 Stephen Daniels 03-JUL-9812121 Jennifer Ames 24-MAY-9722222 Carl Hersey 03-JAN-9823456 Susan Ash 04-MAR-9233333 Nancy Taylor 04-MAR-9234567 Robert Brooks 04-APR-98

6 rows selected.

SQL> SELECT idno AS "ID #", name AS "Donor Name", datefst AS "1st Gave" 2 FROM donor;

COLUMN ALIAS

Donation tableDonation table

IDNO DRI CONTDATE CONTAMT----- --- --------- ---------11111 100 07-JAN-99 2512121 200 23-FEB-99 4023456 100 03-MAR-99 2033333 300 10-MAR-99 1022222 100 14-MAR-99 1012121 100 04-JUN-99 5011111 200 12-JUN-99 3523456 300 14-JUN-99 10

8 rows selected.

The donation table is another sample table we will be looking at. It contains the information about donations that were made. The fields/columns are IDNO, DRIVENO, CONTDATE and CONTAMT.

SQL> SELECT * 2 FROM donation;

SQL statement used to generate the display above.

Donation tableDonation table

SQL> SELECT idno, driveno, contamt, contamt * 2 "NEW GOAL" 2 FROM donation;

IDNO DRI CONTAMT NEW GOAL----- --- --------- ---------11111 100 25 5012121 200 40 8023456 100 20 4033333 300 10 2022222 100 10 2012121 100 50 10011111 200 35 7023456 300 10 20

8 rows selected.In this example, I want to print three fields/columns from the donation table and also the project goal for next year which I have determined is twice the amount donated this year.

Note: The field alias NEW GOAL is given to the column that will contain the contamt *2.

Donor tableDonor table

IDNO NAME STADR CITY ST ZIP DATEFST YRGOAL CONTACT----- --------------- --------------- ---------- -- ----- --------- --------- ------------11111 Stephen Daniels 123 Elm St Seekonk MA 02345 03-JUL-98 500 John Smith12121 Jennifer Ames 24 Benefit St Providence RI 02045 24-MAY-97 400 Susan Jones22222 Carl Hersey 24 Benefit St Providence RI 02045 03-JAN-98 Susan Jones23456 Susan Ash 21 Main St Fall River MA 02720 04-MAR-92 100 Amy Costa33333 Nancy Taylor 26 Oak St Fall River MA 02720 04-MAR-92 50 John Adams34567 Robert Brooks 36 Pine St Fall River MA 02720 04-APR-98 50 Amy Costa

Note the NULL value in YRGOAL. Null values are not the same as zero or space, it is the absence of data.

SQL> SELECT idno, yrgoal, (yrgoal +50)/4 "QUARTERLY GOAL" 2 FROM donor;

IDNO YRGOAL QUARTERLY GOAL----- --------- --------------11111 500 137.512121 400 112.52222223456 100 37.533333 50 2534567 50 25

6 rows selected.

Notice that no results are returned when the field is null or when the null field is used in a calculation.

Donor tableDonor table

SQL> SELECT city || ', ' || state "CITY, STATE" 2 FROM donor;

CITY, STATE--------------Seekonk, MAProvidence, RIProvidence, RIFall River, MAFall River, MAFall River, MA

6 rows selected.

In this example, city is concatenated with a comma followed by a space which is concatenated with state. The column alias of CITY, STATE appears over the resulting column.

Note that the address that is shown is one field. The city is concatenated with the commas and space that is enclosed in single quotes and then concatenated with the state. That results in one field or column.

Note also that the literals that are concatenated with the data are enclosed in single quotes. In this example, the literals are comma plus a space.

SQL> SELECT city || ', ' || state "CITY, STATE" 2 FROM donor;

Command shown again for clarity.

The city is concatenated with a comma and a space: city || ‘, ’. Then this is concatenated with state: ||state. The result is one field containing city and state.

Donor tableDonor table

11111 Stephen Daniels 123 Elm St Seekonk MA 02345 03-JUL-98 500 John Smith12121 Jennifer Ames 24 Benefit St Providence RI 02045 24-MAY-97 400 Susan Jones22222 Carl Hersey 24 Benefit St Providence RI 02045 03-JAN-98 Susan Jones23456 Susan Ash 21 Main St Fall River MA 02720 04-MAR-92 100 Amy Costa33333 Nancy Taylor 26 Oak St Fall River MA 02720 04-MAR-92 50 John Adams34567 Robert Brooks 36 Pine St Fall River MA 02720 04-APR-98 50 Amy Costa

SQL> SELECT DISTINCT contact 2 FROM donor;

CONTACT------------Amy CostaJohn AdamsJohn SmithSusan Jones

In this case Amy Costa appears twice in the data as does Susan Jones. However since we only want distinct occurrences they appear only once in the results of the SELECT.

SQL> SELECT DISTINCT contact, idno, name 2 FROM donor;

CONTACT IDNO NAME------------ ----- ---------------Amy Costa 23456 Susan AshAmy Costa 34567 Robert BrooksJohn Adams 33333 Nancy TaylorJohn Smith 11111 Stephen DanielsSusan Jones 12121 Jennifer AmesSusan Jones 22222 Carl Hersey

Note that DISTINCT did not work when combined with other data fields from the records/rows.

Donor tableDonor tableSQL> SELECT idno, name, yrgoal 2 FROM donor 3 ORDER BY yrgoal;

IDNO NAME YRGOAL----- --------------- ---------33333 Nancy Taylor 5034567 Robert Brooks 5023456 Susan Ash 10012121 Jennifer Ames 40011111 Stephen Daniels 50022222 Carl Hersey

6 rows selected.

The ORDER BY clause shows the data in order by the specified field/column. Ascending is the default order.

Note that the record where yrgoal is NULL appears at the bottom of the list.

SQL> SELECT idno, name, yrgoal 2 FROM donor 3 ORDER BY yrgoal DESC;

IDNO NAME YRGOAL----- --------------- ---------22222 Carl Hersey11111 Stephen Daniels 50012121 Jennifer Ames 40023456 Susan Ash 10033333 Nancy Taylor 5034567 Robert Brooks 50

6 rows selected.

Placing DESC after the name in the ORDER BY clause, sorts in descending order.

Note that the record where yrgoal is NULL now appears at the top of the list.

Donor tableDonor table

SQL> SELECT idno, name, city, state, (yrgoal +50)/4 "QUARTERLY GOAL" 2 FROM donor 3 ORDER BY state DESC, (yrgoal + 50)/4 ASC;

IDNO NAME CITY ST QUARTERLY GOAL----- --------------- ---------- -- --------------12121 Jennifer Ames Providence RI 112.522222 Carl Hersey Providence RI33333 Nancy Taylor Fall River MA 2534567 Robert Brooks Fall River MA 2523456 Susan Ash Fall River MA 37.511111 Stephen Daniels Seekonk MA 137.5

6 rows selected.

The results here include a calculation of quarterly goal. This calculation is also used as the secondary sort.

The primary sort puts the results in order by state in descending order so RI comes before MA.

The secondary sort puts the results in ascending order by the calculated quarterly goal within the state.

Total for RI in ascending order (null at end).

Total for MA in ascending order.