3.   w3schools.com  
    THE WORLD'S LARGEST WEB DEVELOPER SITE
      
        
                      HTML      CSS      JAVASCRIPT      SQL      PYTHON      PHP      BOOTSTRAP      HOW TO      W3.CSS      JQUERY      JAVA      MORE                         FORUM      EXERCISES       REFERENCES     
                  
      
        
    SQL Tutorial
    SQL HOMESQL IntroSQL SyntaxSQL SelectSQL Select DistinctSQL WhereSQL And, Or, NotSQL Order BySQL Insert IntoSQL Null ValuesSQL UpdateSQL DeleteSQL Select TopSQL Min and MaxSQL Count, Avg, SumSQL LikeSQL WildcardsSQL InSQL BetweenSQL AliasesSQL JoinsSQL Inner JoinSQL Left JoinSQL Right JoinSQL Full JoinSQL Self JoinSQL UnionSQL Group BySQL HavingSQL ExistsSQL Any, AllSQL Select IntoSQL Insert Into SelectSQL CaseSQL Null FunctionsSQL Stored ProceduresSQL Comments
    SQL Database
    SQL Create DBSQL Drop DBSQL Backup DBSQL Create TableSQL Drop TableSQL Alter TableSQL ConstraintsSQL Not NullSQL UniqueSQL Primary KeySQL Foreign KeySQL CheckSQL DefaultSQL IndexSQL Auto IncrementSQL DatesSQL ViewsSQL InjectionSQL Hosting
    SQL References
    SQL Keywords
      ADD  ADD CONSTRAINT  ALTER  ALTER COLUMN  ALTER TABLE  ALL  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 OperatorsSQL Data TypesSQL Quick Ref
    SQL Examples
    SQL ExamplesSQL QuizSQL ExercisesSQL Certificate      

        
      
      
        
          
                            
                         
    MySQL IF() Function
    ❮ MySQL Functions
    Example
    Return "YES" if the condition is TRUE, or "NO" if the condition is FALSE:
      SELECT   IF(500<1000, "YES", "NO");
    Try it Yourself »
    Definition and Usage
    The IF() function returns a value if a condition is TRUE, or another value if a condition is FALSE.
    Syntax
      IF(condition, value_if_true, value_if_false)
    Parameter Values
       
        Parameter    Description  
        
        condition    Required. The value to test  
      
        value_if_true    Optional. The value to return if condition is TRUE  
      
        value_if_false    Optional. The value to return if condition is FALSE  
      
    Technical Details
     Works in:  From MySQL 4.0
    More Examples
    Example
    Return 5 if the condition is TRUE, or 10 if the condition is FALSE:
      SELECT IF(500<1000, 5, 10);
    Try it Yourself »
    Example
    Test whether two strings are the same and return "YES" if they are, or "NO" if not:
      SELECT IF(STRCMP("hello","bye") = 0, "YES", "NO");
    Try it Yourself »
    Example
    Return "MORE" if the condition is TRUE, or "LESS" if the condition is FALSE:
      SELECT OrderID, Quantity, IF(Quantity>10, "MORE", "LESS")
    FROM   OrderDetails;
    Try it Yourself »
    ❮ MySQL Functions
        2. 
http://www.mh8dociw.tw |

http://m.mh8dociw.tw |

http://wap.mh8dociw.tw |

http://3g.mh8dociw.tw |

http://4g.mh8dociw.tw |

http://5g.mh8dociw.tw |

http://mobile.mh8dociw.tw |

http://vip.mh8dociw.tw |

http://ios.mh8dociw.tw |

http://anzhuo.mh8dociw.tw |

http://3.mh8dociw.tw |

http://f.mh8dociw.tw |

http://0fb6e0.mh8dociw.tw |

http://bc75ee.mh8dociw.tw |

http://a9e.mh8dociw.tw |

http://db9.mh8dociw.tw |

特级黄毛大片大全在线