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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

SQL ExamplesSQL EditorSQL QuizSQL ExercisesSQL ServerSQL SyllabusSQL Study PlanSQL BootcampSQL CertificateSQL Training

SQLDELETE Statement

The SQL DELETE Statement

TheDELETE statement is used to delete existing records in a table.

DELETE Syntax

DELETE FROMtable_nameWHEREcondition;

Note: Be careful when deleting records in a table! Notice theWHERE clause in theDELETE statement.TheWHERE clause specifies which record(s) should be deleted. If you omit theWHERE clause, all records in the table will be deleted!

Demo Database

Below is a selection from theCustomers table used in the examples:

CustomerIDCustomerNameContactNameAddressCityPostalCodeCountry
1

Alfreds FutterkisteMaria AndersObere Str. 57Berlin12209Germany
2Ana Trujillo Emparedados y heladosAna TrujilloAvda. de la Constitución 2222México D.F.05021Mexico
3Antonio Moreno TaqueríaAntonio MorenoMataderos 2312México D.F.05023Mexico
4

Around the HornThomas Hardy120 Hanover Sq.LondonWA1 1DPUK
5Berglunds snabbköpChristina BerglundBerguvsvägen 8LuleåS-958 22Sweden

SQL DELETE Example

The following SQL statement deletes the customer "Alfreds Futterkiste" from the "Customers" table:

Example

DELETE FROM Customers WHERE CustomerName='Alfreds Futterkiste';

The "Customers" table will now look like this:

CustomerIDCustomerNameContactNameAddressCityPostalCodeCountry
2Ana Trujillo Emparedados y heladosAna TrujilloAvda. de la Constitución 2222México D.F.05021Mexico
3Antonio Moreno TaqueríaAntonio MorenoMataderos 2312México D.F.05023Mexico
4

Around the HornThomas Hardy120 Hanover Sq.LondonWA1 1DPUK
5Berglunds snabbköpChristina BerglundBerguvsvägen 8LuleåS-958 22Sweden

Delete All Records

It is possible to delete all rows in a table without deleting the table. This means that the table structure, attributes, and indexes will be intact:

DELETE FROMtable_name;

The following SQL statement deletes all rows in the "Customers" table, without deleting the table:

Example

DELETE FROM Customers;

Delete a Table

To delete the table completely, use theDROP TABLE statement:

Example

Remove the Customers table:

DROP TABLE Customers;

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