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SQL Tutorial

SQL HOMESQL IntroSQL SyntaxSQL SelectSQL Select DistinctSQL WhereSQL Order BySQL AndSQL OrSQL NotSQL Insert IntoSQL Null ValuesSQL UpdateSQL DeleteSQL Select TopSQL Aggregate FunctionsSQL Min and MaxSQL CountSQL SumSQL AvgSQL LikeSQL WildcardsSQL InSQL BetweenSQL AliasesSQL JoinsSQL Inner JoinSQL Left JoinSQL Right JoinSQL Full JoinSQL Self JoinSQL UnionSQL Union AllSQL Group BySQL HavingSQL ExistsSQL Any, AllSQL Select IntoSQL Insert Into SelectSQL CaseSQL Null FunctionsSQL Stored ProceduresSQL CommentsSQL Operators

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 HostingSQL Data Types

SQL References

SQL KeywordsMySQL Functions
String Functions:ASCIICHAR_LENGTHCHARACTER_LENGTHCONCATCONCAT_WSFIELDFIND_IN_SETFORMATINSERTINSTRLCASELEFTLENGTHLOCATELOWERLPADLTRIMMIDPOSITIONREPEATREPLACEREVERSERIGHTRPADRTRIMSPACESTRCMPSUBSTRSUBSTRINGSUBSTRING_INDEXTRIMUCASEUPPERNumeric Functions:ABSACOSASINATANATAN2AVGCEILCEILINGCOSCOTCOUNTDEGREESDIVEXPFLOORGREATESTLEASTLNLOGLOG10LOG2MAXMINMODPIPOWPOWERRADIANSRANDROUNDSIGNSINSQRTSUMTANTRUNCATEDate Functions:ADDDATEADDTIMECURDATECURRENT_DATECURRENT_TIMECURRENT_TIMESTAMPCURTIMEDATEDATEDIFFDATE_ADDDATE_FORMATDATE_SUBDAYDAYNAMEDAYOFMONTHDAYOFWEEKDAYOFYEAREXTRACTFROM_DAYSHOURLAST_DAYLOCALTIMELOCALTIMESTAMPMAKEDATEMAKETIMEMICROSECONDMINUTEMONTHMONTHNAMENOWPERIOD_ADDPERIOD_DIFFQUARTERSECONDSEC_TO_TIMESTR_TO_DATESUBDATESUBTIMESYSDATETIMETIME_FORMATTIME_TO_SECTIMEDIFFTIMESTAMPTO_DAYSWEEKWEEKDAYWEEKOFYEARYEARYEARWEEKAdvanced Functions:BINBINARYCASECASTCOALESCECONNECTION_IDCONVCONVERTCURRENT_USERDATABASEIFIFNULLISNULLLAST_INSERT_IDNULLIFSESSION_USERSYSTEM_USERUSERVERSION
SQL Server FunctionsMS Access FunctionsSQL Quick Ref

SQL Examples

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SQLDROP DEFAULT Keyword

DROP DEFAULT

TheDROP DEFAULT command is used to delete a DEFAULT constraint.

To drop a DEFAULT constraint, use the following SQL:

SQL Server / Oracle / MS Access:

ALTER TABLE Persons
ALTER COLUMN City DROP DEFAULT;

MySQL:

ALTER TABLE Persons
ALTER City DROP DEFAULT;

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