add labs

lab - cte 101.sql

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+/*
+--Use Cases for CTE's
+1. Replace Temp Tables/Table Vars, change multistep processes to single-query
+2. Recursion (org charts)
+3. Pre-build row-by-row conversions
+*/
+
+with cteSimple as (
+select * from sys.databases)
+select * from cteSimple--;
+
+
+
+
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+
+
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+
+
+with cteSimple (database_name, db_id) as (
+select name, database_id from sys.databases)
+select * from cteSimple 
+
+
+
+
+
+
+
+
+
+
+
+with cteSimple (database_name, database_id) as (
+select name, database_id from sys.databases)
+select * from cteSimple c
+inner join sys.master_files mf on c.database_id = mf.database_id
+
+
+
+
+
+
+
+
+
+
+
+--compare:
+
+--Temp Table
+
+SELECT name, database_id into #TempSimple
+from sys.databases;
+
+select * from #TempSimple c
+inner join sys.master_files mf on c.database_id = mf.database_id;
+
+DROP TABLE IF EXISTS #TempSimple;
+
+--vs 
+
+--CTE 
+with cteSimple (database_name, database_id) as (
+select name, database_id from sys.databases)
+select * from cteSimple c
+inner join sys.master_files mf on c.database_id = mf.database_id;
+
+

lab - cte with dimdate.sql

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+use w
+go
+DROP TABLE IF EXISTS dbo.DimDate 
+GO
+
+CREATE TABLE dbo.DimDate  (
+    [dimDateID]				INT				NOT NULL,
+    [CalendarDate]			DATE			NOT NULL,
+    [Day_of_Month]			TINYINT			NOT NULL,
+    [Day_of_Year]			SMALLINT		NOT NULL,
+    [Day_of_Week]			TINYINT			NOT NULL,
+    [Year]					SMALLINT		NOT NULL,
+    [Quarter]				CHAR (2)		NOT NULL,
+    [Month]					TINYINT			NOT NULL,
+    [Month_Name]			VARCHAR (30)	NOT NULL,
+    [Week_of_Year]			TINYINT			NOT NULL,
+	[DayOfWeek_Month]		TINYINT			NOT NULL,
+    [DayofWeek_Name]		VARCHAR (30)	NOT NULL,
+    [ISOWeek_of_Year]		TINYINT			NOT NULL,
+	[FirstDay_Month]		DATE			NOT NULL,
+	[LastDay_Month]			DATE			NOT NULL,
+	[FirstDay_Year]			DATE			NOT NULL,
+    [IsWeekend]				CHAR (3)		NOT NULL,
+	[IsHoliday]				BIT				NULL,
+	[HolidayText]			VARCHAR(64)		NULL,
+    CONSTRAINT [PK_WH_DimDate] PRIMARY KEY NONCLUSTERED ([CalendarDate] ASC) WITH (DATA_COMPRESSION = PAGE),
+    CONSTRAINT [IDX_NC_DimDate_DimDateID] UNIQUE CLUSTERED ([dimDateID] ASC) WITH (DATA_COMPRESSION = PAGE)
+);
+go
+
+--Bad
+--Antipattern. Takes forever. 
+DROP TABLE IF EXISTS #DimDate
+CREATE TABLE #DimDate (Seeddate date);
+
+INSERT INTO #DimDate (seeddate)
+select seeddate = convert(date, '1/1/2000');
+
+While (Select TOP 1 dateadd(day, 1, seeddate)  from #DimDate) < '1/1/2050'
+INSERT INTO #DimDate 	
+	select TOP 1 dateadd(day, 1, seeddate) 
+	from #DimDate
+	ORDER BY seeddate desc;
+
+
+
+--Better
+
+TRUNCATE TABLE dbo.DimDate;
+
+
+SET STATISTICS IO ON
+DROP TABLE IF EXISTS #DimDate
+CREATE TABLE #DimDate (Seeddate date) 
+
+;with cteDate (seeddate) as 
+	(
+	select seeddate = convert(date, '1/1/2000') 
+	UNION ALL
+	select dateadd(day, 1, seeddate) 
+	from cteDate
+	where seeddate < '1/1/2050'
+	)
+INSERT INTO #DimDate
+SELECT seeddate from cteDate
+OPTION (MAXRECURSION 0);
+
+insert into dbo.DimDate (dimDateID, CalendarDate, Day_of_Month, Day_of_Year, Day_of_Week, Year, Quarter, Month, Month_Name, DayOfWeek_Month, Week_of_Year, DayofWeek_Name, ISOWeek_of_Year, FirstDay_Month, LastDay_Month, FirstDay_Year, IsWeekend)
+		select 
+			dimDateID			=	convert(int,convert(varchar(8),seeddate, 112))
+		,	CalendarDate		=	seeddate
+		,	Day_of_Month		=	DatePart(d, seeddate)
+		,	Day_of_Year			=	DatePart(dy, seeddate)
+		,	Day_of_Week			=	DatePart(dw, seeddate)
+		,	[Year]				=	DatePart(yyyy, seeddate)
+		,	[Quarter]			=	'Q' + Convert(char(1), datepart(quarter , seeddate))
+		,	[Month]				=	DatePart(M, seeddate)
+		,	[Month_Name]		=	DateName(m, seeddate) 
+		,   [DayOfWeek_Month]   =	CONVERT(TINYINT, ROW_NUMBER() OVER 
+									(PARTITION BY (CONVERT(DATE, DATEADD(MONTH, DATEDIFF(MONTH, 0, seeddate), 0))), DatePart(dw, seeddate) ORDER BY seeddate))
+		,	Week_of_Year		=	DatePart(week, seeddate) 
+		,	DayofWeek_Name		=	DateName(dw, seeddate) 
+		,	ISOWeek_of_Year		=	DatePart(ISO_WEEK, seeddate) 
+		,	[FirstDay_Month]	=	CONVERT(DATE, DATEADD(MONTH, DATEDIFF(MONTH, 0, seeddate), 0))
+		,	[LastDay_Month]		=	MAX(seeddate) OVER (PARTITION BY DatePart(yyyy, seeddate), DatePart(M, seeddate))
+		,	[FirstDay_Year]		=	CONVERT(DATE, DATEADD(YEAR,  DATEDIFF(YEAR,  0, seeddate), 0))
+		,	IsWeekend			=	CASE WHEN DatePart(dw, seeddate) in (1,7) THEN 'Yes' ELSE 'No' END
+from #DimDate
+where seeddate < '1/1/2050'
+SET STATISTICS IO OFF
+GO
+
+
+
+
+
+
+
+
+--Best
+--
+--Takes 2-3s to create 18263 records
+
+TRUNCATE TABLE dbo.DimDate;
+SET STATISTICS IO ON
+;with cteDate (seeddate) as
+	(
+	select seeddate = convert(date, '1/1/2000') 
+	UNION ALL
+	select dateadd(day, 1, seeddate) 
+	from cteDate
+	where seeddate < '1/1/2050'
+) 
+
+insert into dbo.DimDate (dimDateID, CalendarDate, Day_of_Month, Day_of_Year, Day_of_Week, Year, Quarter, Month, Month_Name, DayOfWeek_Month, Week_of_Year, DayofWeek_Name, ISOWeek_of_Year, FirstDay_Month, LastDay_Month, FirstDay_Year, IsWeekend)
+		select 
+			dimDateID			=	convert(int,convert(varchar(8),seeddate, 112))
+		,	CalendarDate		=	seeddate
+		,	Day_of_Month		=	DatePart(d, seeddate)
+		,	Day_of_Year			=	DatePart(dy, seeddate)
+		,	Day_of_Week			=	DatePart(dw, seeddate)
+		,	[Year]				=	DatePart(yyyy, seeddate)
+		,	[Quarter]			=	'Q' + Convert(char(1), datepart(quarter , seeddate))
+		,	[Month]				=	DatePart(M, seeddate)
+		,	[Month_Name]		=	DateName(m, seeddate) 
+		,   [DayOfWeek_Month]   =	CONVERT(TINYINT, ROW_NUMBER() OVER 
+									(PARTITION BY (CONVERT(DATE, DATEADD(MONTH, DATEDIFF(MONTH, 0, seeddate), 0))), DatePart(dw, seeddate) ORDER BY seeddate))
+		,	Week_of_Year		=	DatePart(week, seeddate) 
+		,	DayofWeek_Name		=	DateName(dw, seeddate) 
+		,	ISOWeek_of_Year		=	DatePart(ISO_WEEK, seeddate) 
+		,	[FirstDay_Month]	=	CONVERT(DATE, DATEADD(MONTH, DATEDIFF(MONTH, 0, seeddate), 0))
+		,	[LastDay_Month]		=	MAX(seeddate) OVER (PARTITION BY DatePart(yyyy, seeddate), DatePart(M, seeddate))
+		,	[FirstDay_Year]		=	CONVERT(DATE, DATEADD(YEAR,  DATEDIFF(YEAR,  0, seeddate), 0))
+		,	IsWeekend			=	CASE WHEN DatePart(dw, seeddate) in (1,7) THEN 'Yes' ELSE 'No' END
+from cteDate
+where seeddate < '1/1/2050'
+OPTION (MAXRECURSION 0);
+SET STATISTICS IO OFF
+GO
+
+
+