SQL 实例

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SQL 语法

Select all the records from a specific table ("Customers")

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SQL SELECT

SELECT Column SELECT *

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SQL SELECT DISTINCT

SELECT DISTINCT SELECT COUNT(DISTINCT column_name) SELECT COUNT(DISTINCT column_name) workaround for MS Access

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SQL WHERE

WHERE Clause Text Fields vs. Numeric Fields

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SQL AND, OR and NOT Operators

AND OR NOT Combining AND, OR and NOT

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SQL ORDER BY

ORDER BY ORDER BY DESC ORDER BY Several Columns

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SQL INSERT INTO

INSERT INTO Insert data in specific columns

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SQL NULL Values

IS NULL Operator IS NOT NULL Operator

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SQL Update

UPDATE Table UPDATE Multiple Records UPDATE Warning (if you omit the WHERE clause, all records will be updated)

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SQL DELETE

DELETE DELETE All Records

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SQL SELECT TOP

SELECT TOP LIMIT SELECT TOP PERCENT SELECT TOP and add a WHERE Clause

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SQL MIN() and MAX()

MIN() MAX()

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SQL COUNT, AVG() and SUM()

COUNT() AVG() SUM()

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SQL LIKE

LIKE - select all table rows starting with "a" LIKE - select all table rows ending with "a" LIKE - select all table rows that have "or" in any position LIKE - select all table rows that have "r" in the second position LIKE - select all table rows that starts with "a" and ends with "o" LIKE - select all table rows that does NOT start with "a"

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SQL Wildcards

Using the % Wildcard Using the _ Wildcard Using the [charlist] Wildcard Using the [!charlist] Wildcard

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SQL IN

IN NOT IN

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SQL BETWEEN

BETWEEN NOT BETWEEN BETWEEN with IN BETWEEN Text Values NOT BETWEEN Text Values

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SQL Aliases

Alias for Columns Two Aliases Alias for Tables

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SQL Joins

INNER JOIN LEFT JOIN RIGHT JOIN Self JOIN

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SQL UNION

UNION UNION ALL UNION With WHERE UNION ALL With WHERE

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SQL GROUP BY

GROUP BY GROUP BY and ORDER BY GROUP BY With JOIN

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SQL HAVING

HAVING and GROUP BY HAVING and ORDER BY

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SQL EXISTS

EXISTS

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SQL ANY and ALL

ANY ALL

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SQL INSERT INTO SELECT

INSERT INTO SELECT INSERT INTO SELECT with WHERE

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SQL CASE

CASE 1 CASE 2

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SQL Comments

Single Line Comments Single Line Comments At The End Of a Line Multi-line Comments

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SQL Database

SQL Database tutorials can be found here:

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 Index SQL Auto Increment SQL Dates SQL Views SQL Injection SQL Hosting

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