basic sql statementschientt

8/8/2019 Basic SQL StatementsChienTT

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Copyright 2006 FPT Software 1 FPT SOFTWARE TRAINING MATERIAL 04e-BM/DT/HDCV/FSOFT v2.2

Author:oang Tuyet Nhung - QA G8

Instructor: Tran Thanh Chien QA G2

Basic SQL statementsBasic SQL statements


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Purpose:

Provide understanding and using SQL statements

Targeted attendees:

Testers

SQA

Estimated duration: 2hours

Introduction


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Afterthe course, studentwill be ableto:Know how touse SQLstatementsto query and manipulateinformation contained withinarelational database

The basic components of a SELECT statement used to queryinformation held on a database

Returningunique information using the DISTINCT clause.

Sorting the information returned via the ORDER BY clause.

Limiting the information returned by the WHERE clause.

Manipulating data contained within the database using basicINSERT, UPDATE and DELETE statements.

Objectives


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Basic SQL statements


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CREATE TABLE statement

CREATETABLEtable_name(column1 data_type_for_column_1,column2 data_type_for_column_2,

... );

Explanation:Createatable withnametable_name andhave column1, column2


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Example: CREATE TABLE customer (First_Name char(50), Last_Name

char(50),Address char(50), City char(50), Country char(25), DOB date);

To specify a default value, add "Default [value]" after the data typedeclaration. In the above example, if we want to default column"Address" to "Unknown" and City to Hanoi", we would type in:

CREATE TABLE customer (First_Name char(50), Last_Namechar(50),

Address char(50) default 'Unknown', City char(50) default Hanoi',Country char(25), DOB date);

CREATECREATE TABLE statementTABLE statement


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SELECT statement

SELECT column_listFROMtable_list; --thesimplest

SELECT * FROM employee; -- listall rows with

all fieldsintable SELECT col1, col2, col3 FROM employee; -- listall rows with 3 fieldsfromtable


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Comparison

SE

LEC

T column-listFROM table_list

[WHERE condition]; --Comparison Operators: =,!=,,=

Example:

SELECT empno,surname

FROM employeeWHERE depno= 3;

SELECT forenames,surname

FROM employee

WHERE dob> 2-jan-1958;


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SELECT with BEWEEN

SELECT empno, surname, forenames, dob

FROM employee

WHERE dob BETWEEN 30-jun-1954 AND 1-jan-1959;

Note that the BETWEEN predic ate is inclusive. The above conditionis equivalent to:

WHERE dob>= 30-jun-1954 AND


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Pattern matching

Simple pattern matching is carried out using LIKE

LIKE pattern-to-matchWhere the pattern can include special wildcard

characters:

% 0 or more arbitrary characters_ any one character

Example:

SELECT forenames, surname, address

FROM employee

WHERE address LIKE %Edinburgh%;


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ORDER and DISTINCT


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A SELECT query can be used within another SELECT condition and isthen known as a subquery

A subquery can return onlyone attribute having zeroor more values

The use of a view mayprovide a simpler queryformat than usingtechniques such as self-joins

Operations with subquery: >, =, ( Select dob

From employee

Where forename=Viet and surname =Anh)

Subqueries


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Example 2: List the names and employee numbers of all those whohave never been on a training course:

SELECT empno,forenames,surname

FROM employee

WHERE empno NOT IN

(SELECT DISTINCT empnoFROM empcourse);

Example3: List the numberof each employee in departments HCD orFAF, plus employees who join course Test pool:

(SELECT empno

FROM employee

WHERE depname IN (HCD,FAF)) UNION (SELECT empno FROM course, empcourse

WHERE course.courseno=empcourse.courseno

AND course.cname like %Test Pool%)

Subqueries (cont)


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INSERT INTO table_name [(column list)]

VALUES (value list)

The column_list can be omited if every columns is to be assigned avalue, otherwise it must list columns to be assigned values.

The value_list is a set of literal values giving the value of eachcolumn in the same order as the column_list, if specified, or as thecolumns are defined in the original CREATE TABLE.

Example:

INSERT INTO course

Values (11,Advanced Accounting,10-jan-2000);

INSERT INTO course (courseno, cname)

Values(13,Advanced Administration);

INSERT


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DELETE FROM table_name

[WHERE condition];

Explanation: the rows of table_namewhich satifythe condition aredeleted.

Example:

DELETE FROM employee; -- delete all rows in employee table, leavingan empty table

DELETE FROM employee WHERE dob>10/07/2000 deleteemployee that have date of birth after 10/7/2000.

DROP table_name;

DROP employee; --remove employee table completely

DELETE/DROP


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UPDATE table_name

SET column_name(s) = expression(s) [WHERE condition];

The expression can be

NULL

A literal value

An expression based upon the current column value

Example: Give a salaryrise of 10% to all testers

UPDATE Salary

SET empsal =empsal *1.10

WHEREposition LIKE %TESTER%

UPDATE


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Create a DB with name Pool12 have 3tables as description inscript.txtfile

Practise:

1. List all students of Tin1class

2. List out student have highest mark of

Tin1class3. Count all students of IT faculty

4. Count students of each class

5. Add student(s) into DB

6. Update student marks: if mark


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SQL Command

SQL SELECT

SQL DISTINCT

SQL WHERE

SQL AND OR

SQL INSQL BETWEEN

SQL LIKE

SQL ORDER BY

SQL Functions

SQL COUNT

SQL GROUP BYSQL HAVING

SQL ALIAS

SQL JOIN

SQL OUTER JOIN

SQL CONCATENATE

SQL SUBSTRINGSQL TRIM

Table Manipulation

SQL CREATE TABLE

SQL CONSTRAINTSQL PRIMARY KEY

SQL FOREIGN KEY

SQL CREATE VIEW

SQL CREATE INDEX

SQL ALTER TABLE

SQL DROP TABLESQL TRUNCATE TABLE

SQL INSERT INTO

SQL UPDATE

SQL DELETE FROM

SQL Command & Table Manipulation

c1

c2

c3c4


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Slide 18

c1 - AVG- COUNT

- MAX

- MIN- SUMchientt, 10/2/2007

c2 MySQL:CONCAT()

Oracle:CONCAT(), ||

SQLServer: +chientt, 10/2/2007

c3 MySQL:SUBSTR(), SUBSTRING()

Oracle:SUBSTR()

SQLServer:SUBSTRING()chientt, 10/2/2007

c4 MySQL:TRIM(), RTRIM(), LTRIM()

Oracle:RTRIM(), LTRIM()SQLServer:RTRIM(), LTRIM()

TRIM([[LOCATION][remstr] FROM]str):[LOCATION] can be eitherLEADING, TRAILING, orBOTH. Thisfunction getsridofthe[remstr]patternfrom eitherthe beginningofthestringorthe endofthestring, or both. Ifno[remstr]isspecified, whitespacesare

removed.

LTRIM(str):Removesall whitespacesfromthe beginningofthestring.

RTRIM(str):Removesall whitespacesatthe endofthestring.chientt, 10/2/2007


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SQL UNION

SQL UNION ALL

SQL INTERSECTSQL MINUS

SQL Subquery

SQL EXISTSSQL CASE

SQL Advance

c5

c6

c7


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Slide 19

c5 ThepurposeoftheSQLUNION commandisto combinetheresultsoftwo queriestogether. Inthisrespect, UNIONissomewhat

similarto JOINinthatthey are bothusedtorelatedinformationfrommultipletables. OnerestrictionofUNIONisthatall

corresponding columnsneedto beofthesamedatatype. Also, whenusingUNION, only distinctvaluesareselectedchientt, 10/2/2007

c6 ThepurposeoftheSQLUNIONALL commandisalsoto combinetheresultsoftwo queriestogether. Thedifference betweenUNIONALLandUNIONisthat, whileUNIONonly selectsdistinctvalues, UNIONALLselectsall values.

ThesyntaxforUNIONALLisasfollows:[SQLStatement1]UNIONALL[SQLStatement2]chientt, 10/2/2007

c7 SimilartotheUNION command, INTERSECTalsooperatesontwoSQLstatements. Thedifferenceisthat, whileUNION essentially

actsasanORoperator(valueisselectedifitappearsin eitherthefirstorthesecondstatement), theINTERSECT commandactsasanANDoperator(valueisselectedonly ifitappearsin bothstatements).Thesyntaxisasfollows:[SQLStatement1]

INTERSECT

[SQLStatement2]chientt, 10/2/2007


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Table & Relationship


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basic sql statementschientt

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