SQLの紹介

SQL Introduction Menu Search field × See More Sign In ★ +1 Get Certified Upgrade Teachers Spaces Bootcamps Get Certified Upgrade Teachers Spaces Bootcamps ❮ ❯ HTML CSS JAVASCRIPT SQL PYTHON JAVA PHP HOW TO W3.CSS C C++ C# BOOTSTRAP REACT MYSQL JQUERY EXCEL XML DJANGO NUMPY PANDAS NODEJS DSA TYPESCRIPT ANGULAR ANGULARJS GIT POSTGRESQL MONGODB ASP AI R GO KOTLIN SWIFT SASS VUE GEN AI SCIPY AWS CYBERSECURITY DATA SCIENCE INTRO TO PROGRAMMING INTRO TO HTML & CSS BASH RUST TOOLS SQL Tutorial SQL HOME SQL Intro SQL Syntax SQL Select SQL Select Distinct SQL Where SQL Order By SQL And SQL Or SQL Not SQL Insert Into SQL Null Values SQL Update SQL Delete SQL Select Top SQL Aggregate Functions SQL Min() SQL Max() SQL Count() SQL Sum() SQL Avg() SQL Like SQL Wildcards SQL In SQL Between SQL Aliases SQL Joins SQL Inner Join SQL Left Join SQL Right Join SQL Full Join SQL Self Join SQL Union SQL Union All SQL Group By SQL Having SQL Exists SQL Any SQL All SQL Select Into SQL Insert Into Select SQL Case SQL Null Functions SQL Stored Procedures SQL Comments SQL Operators SQL Database SQL Create DB SQL Drop DB SQL Backup DB SQL Create Table SQL Drop Table SQL Alter Table SQL Constraints SQL Not Null SQL Unique SQL Primary Key SQL Foreign Key SQL Check SQL Default SQL Create Index SQL Auto Increment SQL Dates SQL Views SQL Injection SQL Parameters SQL Prepared Statements SQL Hosting SQL Cert SQL Certificate SQL References SQL Data Types SQL Keywords ADD ADD CONSTRAINT ALL ALTER ALTER COLUMN ALTER TABLE ALTER VIEW AND ANY AS ASC BACKUP DATABASE BETWEEN CASE CHECK COLUMN CONSTRAINT CREATE CREATE DATABASE CREATE INDEX CREATE OR REPLACE VIEW CREATE TABLE CREATE PROCEDURE CREATE UNIQUE INDEX CREATE VIEW DATABASE DEFAULT DELETE DESC DISTINCT DROP DROP COLUMN DROP CONSTRAINT DROP DATABASE DROP DEFAULT DROP INDEX DROP TABLE DROP VIEW EXEC EXISTS FOREIGN KEY FROM FULL OUTER JOIN GROUP BY HAVING IN INDEX INNER JOIN INSERT INTO INSERT INTO SELECT IS NULL IS NOT NULL JOIN LEFT JOIN LIKE LIMIT NOT NOT NULL OR ORDER BY OUTER JOIN PRIMARY KEY PROCEDURE RIGHT JOIN ROWNUM SELECT SELECT DISTINCT SELECT INTO SELECT TOP SET TABLE TOP TRUNCATE TABLE UNION UNION ALL UNIQUE UPDATE VALUES VIEW WHERE MySQL Functions String Functions: ASCII CHAR_LENGTH CHARACTER_LENGTH CONCAT CONCAT_WS FIELD FIND_IN_SET FORMAT INSERT INSTR LCASE LEFT LENGTH LOCATE LOWER LPAD LTRIM MID POSITION REPEAT REPLACE REVERSE RIGHT RPAD RTRIM SPACE STRCMP SUBSTR SUBSTRING SUBSTRING_INDEX TRIM UCASE UPPER Numeric Functions: ABS ACOS ASIN ATAN ATAN2 AVG CEIL CEILING COS COT COUNT DEGREES DIV EXP FLOOR GREATEST LEAST LN LOG LOG10 LOG2 MAX MIN MOD PI POW POWER RADIANS RAND ROUND SIGN SIN SQRT SUM TAN TRUNCATE Date Functions: ADDDATE ADDTIME CURDATE CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP CURTIME DATE DATEDIFF DATE_ADD DATE_FORMAT DATE_SUB DAY DAYNAME DAYOFMONTH DAYOFWEEK DAYOFYEAR EXTRACT FROM_DAYS HOUR LAST_DAY LOCALTIME LOCALTIMESTAMP MAKEDATE MAKETIME MICROSECOND MINUTE MONTH MONTHNAME NOW PERIOD_ADD PERIOD_DIFF QUARTER SECOND SEC_TO_TIME STR_TO_DATE SUBDATE SUBTIME SYSDATE TIME TIME_FORMAT TIME_TO_SEC TIMEDIFF TIMESTAMP TO_DAYS WEEK WEEKDAY WEEKOFYEAR YEAR YEARWEEK Advanced Functions: BIN BINARY CASE CAST COALESCE CONNECTION_ID CONV CONVERT CURRENT_USER DATABASE IF IFNULL ISNULL LAST_INSERT_ID NULLIF SESSION_USER SYSTEM_USER USER VERSION SQL Server Functions String Functions: ASCII CHAR CHARINDEX CONCAT Concat with + CONCAT_WS DATALENGTH DIFFERENCE FORMAT LEFT LEN LOWER LTRIM NCHAR PATINDEX QUOTENAME REPLACE REPLICATE REVERSE RIGHT RTRIM SOUNDEX SPACE STR STUFF SUBSTRING TRANSLATE TRIM UNICODE UPPER Numeric Functions: ABS ACOS ASIN ATAN ATN2 AVG CEILING COUNT COS COT DEGREES EXP FLOOR LOG LOG10 MAX MIN PI POWER RADIANS RAND ROUND SIGN SIN SQRT SQUARE SUM TAN Date Functions: CURRENT_TIMESTAMP DATEADD DATEDIFF DATEFROMPARTS DATENAME DATEPART DAY GETDATE GETUTCDATE ISDATE MONTH SYSDATETIME YEAR Advanced Functions CAST COALESCE CONVERT CURRENT_USER IIF ISNULL ISNUMERIC NULLIF SESSION_USER SESSIONPROPERTY SYSTEM_USER USER_NAME MS Access Functions String Functions: Asc Chr Concat with & CurDir Format InStr InstrRev LCase Left Len LTrim Mid Replace Right RTrim Space Split Str StrComp StrConv StrReverse Trim UCase Numeric Functions: Abs Atn Avg Cos Count Exp Fix Format Int Max Min Randomize Rnd Round Sgn Sqr Sum Val Date Functions: Date DateAdd DateDiff DatePart DateSerial DateValue Day Format Hour Minute Month MonthName Now Second Time TimeSerial TimeValue Weekday WeekdayName Year Other Functions: CurrentUser Environ IsDate IsNull IsNumeric SQL Quick Ref SQL Examples SQL Examples SQL Editor SQL Quiz SQL Exercises SQL Server SQL Syllabus SQL Study Plan SQL Bootcamp SQL Training Introduction to SQL ❮ Previous Next ❯ What is SQL? SQL is a standard language for accessing and manipulating databases. SQL stands for Structured Query Language SQL lets you access and manipulate databases SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987 What Can SQL do? SQL can execute queries against a database SQL can retrieve data from a database SQL can insert records in a database SQL can update records in a database SQL can delete records from a database SQL can create new databases SQL can create new tables in a database SQL can create stored procedures in a database SQL can create views in a database SQL can set permissions on tables, procedures, and views SQL is a Standard - BUT.... Although SQL is an ANSI/ISO standard, there are different versions of the SQL language. However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT , UPDATE , DELETE , INSERT , WHERE ) in a similar manner. Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard! Using SQL in Your Web Site To build a web site that shows data from a database, you will need: An RDBMS database program (i.e. MS Access, SQL Server, MySQL) To use a server-side scripting language, like PHP or ASP To use SQL to get the data you want To use HTML / CSS to style the page RDBMS RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. The data in RDBMS is stored in database objects called tables. A table is a collection of related data entries and it consists of columns and rows. Look at the "Customers" table: Example SELECT * FROM Customers; Try it Yourself » The columns in the "Customers" table consist of CustomerID, CustomerName, ContactName, Address, City, PostalCode and Country. A column is a vertical entity in a table. A record, also called a row, is each individual entry that exists in a table. For example, there are 91 records in the above Customers table. A record is a horizontal entity in a table. Video: SQL Introduction ❮ Previous Next ❯ ★ +1 Sign in to track progress COLOR PICKER REMOVE ADS PLUS SPACES GET CERTIFIED FOR TEACHERS BOOTCAMPS CONTACT US × Contact Sales If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: [email protected] Report Error If you want to report an error, or if you want to make a suggestion, send us an e-mail: [email protected] Top Tutorials HTML Tutorial CSS Tutorial JavaScript Tutorial How To Tutorial SQL Tutorial Python Tutorial W3.CSS Tutorial Bootstrap Tutorial PHP Tutorial Java Tutorial C++ Tutorial jQuery Tutorial Top References HTML Reference CSS Reference JavaScript Reference SQL Reference Python Reference W3.CSS Reference Bootstrap Reference PHP Reference HTML Colors Java Reference AngularJS Reference jQuery Reference Top Examples HTML Examples CSS Examples JavaScript Examples How To Examples SQL Examples Python Examples W3.CSS Examples Bootstrap Examples PHP Examples Java Examples XML Examples jQuery Examples Get Certified HTML Certificate CSS Certificate JavaScript Certificate Front End Certificate SQL Certificate Python Certificate PHP Certificate jQuery Certificate Java Certificate C++ Certificate C# Certificate XML Certificate     FORUM ABOUT ACADEMY W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use , cookies and privacy policy . Copyright 1999-2026 by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3.CSS . -->