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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

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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
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SQLAggregate Functions

SQL Aggregate Functions

An aggregate function is a function that performs a calculation on a set of values, and returns a single value.

Aggregate functions are often used with theGROUP BY clause of theSELECT statement. TheGROUP BY clause splits the result-set into groups of values and the aggregate function can be used to return a single value for each group.

The most commonly used SQL aggregate functions are:

  • MIN() - returns the smallest value within the selected column
  • MAX() - returns the largest value within the selected column
  • COUNT() - returns the number of rows in a set
  • SUM() - returns the total sum of a numerical column
  • AVG() - returns the average value of a numerical column

Aggregate functions ignore null values (except forCOUNT(*)).

We will go through the aggregate functions above in the next chapters.


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