300 lines
8.7 KiB
SQL
300 lines
8.7 KiB
SQL
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-- Practical SQL: A Beginner's Guide to Storytelling with Data
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-- by Anthony DeBarros
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-- Chapter 8 Code Examples
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--------------------------------------------------------------
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-- Listing 8-1: Creating and filling the 2014 Public Libraries Survey table
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CREATE TABLE pls_fy2014_pupld14a (
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stabr varchar(2) NOT NULL,
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fscskey varchar(6) CONSTRAINT fscskey2014_key PRIMARY KEY,
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libid varchar(20) NOT NULL,
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libname varchar(100) NOT NULL,
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obereg varchar(2) NOT NULL,
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rstatus integer NOT NULL,
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statstru varchar(2) NOT NULL,
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statname varchar(2) NOT NULL,
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stataddr varchar(2) NOT NULL,
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longitud numeric(10,7) NOT NULL,
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latitude numeric(10,7) NOT NULL,
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fipsst varchar(2) NOT NULL,
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fipsco varchar(3) NOT NULL,
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address varchar(35) NOT NULL,
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city varchar(20) NOT NULL,
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zip varchar(5) NOT NULL,
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zip4 varchar(4) NOT NULL,
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cnty varchar(20) NOT NULL,
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phone varchar(10) NOT NULL,
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c_relatn varchar(2) NOT NULL,
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c_legbas varchar(2) NOT NULL,
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c_admin varchar(2) NOT NULL,
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geocode varchar(3) NOT NULL,
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lsabound varchar(1) NOT NULL,
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startdat varchar(10),
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enddate varchar(10),
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popu_lsa integer NOT NULL,
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centlib integer NOT NULL,
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branlib integer NOT NULL,
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bkmob integer NOT NULL,
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master numeric(8,2) NOT NULL,
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libraria numeric(8,2) NOT NULL,
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totstaff numeric(8,2) NOT NULL,
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locgvt integer NOT NULL,
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stgvt integer NOT NULL,
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fedgvt integer NOT NULL,
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totincm integer NOT NULL,
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salaries integer,
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benefit integer,
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staffexp integer,
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prmatexp integer NOT NULL,
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elmatexp integer NOT NULL,
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totexpco integer NOT NULL,
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totopexp integer NOT NULL,
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lcap_rev integer NOT NULL,
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scap_rev integer NOT NULL,
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fcap_rev integer NOT NULL,
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cap_rev integer NOT NULL,
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capital integer NOT NULL,
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bkvol integer NOT NULL,
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ebook integer NOT NULL,
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audio_ph integer NOT NULL,
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audio_dl float NOT NULL,
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video_ph integer NOT NULL,
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video_dl float NOT NULL,
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databases integer NOT NULL,
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subscrip integer NOT NULL,
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hrs_open integer NOT NULL,
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visits integer NOT NULL,
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referenc integer NOT NULL,
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regbor integer NOT NULL,
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totcir integer NOT NULL,
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kidcircl integer NOT NULL,
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elmatcir integer NOT NULL,
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loanto integer NOT NULL,
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loanfm integer NOT NULL,
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totpro integer NOT NULL,
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totatten integer NOT NULL,
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gpterms integer NOT NULL,
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pitusr integer NOT NULL,
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wifisess integer NOT NULL,
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yr_sub integer NOT NULL
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);
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CREATE INDEX libname2014_idx ON pls_fy2014_pupld14a (libname);
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CREATE INDEX stabr2014_idx ON pls_fy2014_pupld14a (stabr);
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CREATE INDEX city2014_idx ON pls_fy2014_pupld14a (city);
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CREATE INDEX visits2014_idx ON pls_fy2014_pupld14a (visits);
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COPY pls_fy2014_pupld14a
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FROM 'C:\YourDirectory\pls_fy2014_pupld14a.csv'
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WITH (FORMAT CSV, HEADER);
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-- Listing 8-2: Creating and filling the 2009 Public Libraries Survey table
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CREATE TABLE pls_fy2009_pupld09a (
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stabr varchar(2) NOT NULL,
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fscskey varchar(6) CONSTRAINT fscskey2009_key PRIMARY KEY,
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libid varchar(20) NOT NULL,
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libname varchar(100) NOT NULL,
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address varchar(35) NOT NULL,
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city varchar(20) NOT NULL,
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zip varchar(5) NOT NULL,
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zip4 varchar(4) NOT NULL,
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cnty varchar(20) NOT NULL,
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phone varchar(10) NOT NULL,
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c_relatn varchar(2) NOT NULL,
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c_legbas varchar(2) NOT NULL,
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c_admin varchar(2) NOT NULL,
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geocode varchar(3) NOT NULL,
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lsabound varchar(1) NOT NULL,
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startdat varchar(10),
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enddate varchar(10),
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popu_lsa integer NOT NULL,
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centlib integer NOT NULL,
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branlib integer NOT NULL,
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bkmob integer NOT NULL,
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master numeric(8,2) NOT NULL,
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libraria numeric(8,2) NOT NULL,
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totstaff numeric(8,2) NOT NULL,
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locgvt integer NOT NULL,
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stgvt integer NOT NULL,
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fedgvt integer NOT NULL,
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totincm integer NOT NULL,
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salaries integer,
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benefit integer,
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staffexp integer,
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prmatexp integer NOT NULL,
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elmatexp integer NOT NULL,
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totexpco integer NOT NULL,
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totopexp integer NOT NULL,
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lcap_rev integer NOT NULL,
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scap_rev integer NOT NULL,
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fcap_rev integer NOT NULL,
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cap_rev integer NOT NULL,
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capital integer NOT NULL,
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bkvol integer NOT NULL,
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ebook integer NOT NULL,
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audio integer NOT NULL,
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video integer NOT NULL,
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databases integer NOT NULL,
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subscrip integer NOT NULL,
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hrs_open integer NOT NULL,
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visits integer NOT NULL,
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referenc integer NOT NULL,
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regbor integer NOT NULL,
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totcir integer NOT NULL,
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kidcircl integer NOT NULL,
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loanto integer NOT NULL,
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loanfm integer NOT NULL,
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totpro integer NOT NULL,
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totatten integer NOT NULL,
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gpterms integer NOT NULL,
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pitusr integer NOT NULL,
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yr_sub integer NOT NULL,
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obereg varchar(2) NOT NULL,
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rstatus integer NOT NULL,
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statstru varchar(2) NOT NULL,
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statname varchar(2) NOT NULL,
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stataddr varchar(2) NOT NULL,
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longitud numeric(10,7) NOT NULL,
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latitude numeric(10,7) NOT NULL,
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fipsst varchar(2) NOT NULL,
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fipsco varchar(3) NOT NULL
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);
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CREATE INDEX libname2009_idx ON pls_fy2009_pupld09a (libname);
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CREATE INDEX stabr2009_idx ON pls_fy2009_pupld09a (stabr);
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CREATE INDEX city2009_idx ON pls_fy2009_pupld09a (city);
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CREATE INDEX visits2009_idx ON pls_fy2009_pupld09a (visits);
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COPY pls_fy2009_pupld09a
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FROM 'C:\YourDirectory\pls_fy2009_pupld09a.csv'
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WITH (FORMAT CSV, HEADER);
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-- Listing 8-3: Using count() for table row counts
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SELECT count(*)
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FROM pls_fy2014_pupld14a;
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SELECT count(*)
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FROM pls_fy2009_pupld09a;
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-- Listing 8-4: Using count() for the number of values in a column
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SELECT count(salaries)
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FROM pls_fy2014_pupld14a;
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-- Listing 8-5: Using count() for the number of distinct values in a column
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SELECT count(libname)
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FROM pls_fy2014_pupld14a;
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SELECT count(DISTINCT libname)
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FROM pls_fy2014_pupld14a;
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-- Bonus: find duplicate libnames
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SELECT libname, count(libname)
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FROM pls_fy2014_pupld14a
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GROUP BY libname
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ORDER BY count(libname) DESC;
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-- Bonus: see location of every Oxford Public Library
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SELECT libname, city, stabr
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FROM pls_fy2014_pupld14a
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WHERE libname = 'OXFORD PUBLIC LIBRARY';
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-- Listing 8-6: Finding the most and fewest visits using max() and min()
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SELECT max(visits), min(visits)
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FROM pls_fy2014_pupld14a;
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-- Listing 8-7: Using GROUP BY on the stabr column
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-- There are 56 in 2014.
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SELECT stabr
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FROM pls_fy2014_pupld14a
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GROUP BY stabr
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ORDER BY stabr;
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-- Bonus: there are 55 in 2009.
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SELECT stabr
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FROM pls_fy2009_pupld09a
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GROUP BY stabr
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ORDER BY stabr;
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-- Listing 8-8: Using GROUP BY on the city and stabr columns
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SELECT city, stabr
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FROM pls_fy2014_pupld14a
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GROUP BY city, stabr
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ORDER BY city, stabr;
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-- Bonus: We can count some of the combos
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SELECT city, stabr, count(*)
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FROM pls_fy2014_pupld14a
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GROUP BY city, stabr
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ORDER BY count(*) DESC;
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-- Listing 8-9: GROUP BY with count() on the stabr column
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SELECT stabr, count(*)
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FROM pls_fy2014_pupld14a
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GROUP BY stabr
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ORDER BY count(*) DESC;
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-- Listing 8-10: GROUP BY with count() on the stabr and stataddr columns
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SELECT stabr, stataddr, count(*)
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FROM pls_fy2014_pupld14a
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GROUP BY stabr, stataddr
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ORDER BY stabr ASC, count(*) DESC;
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-- Listing 8-11: Using the sum() aggregate function to total visits to
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-- libraries in 2014 and 2009
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-- 2014
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SELECT sum(visits) AS visits_2014
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FROM pls_fy2014_pupld14a
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WHERE visits >= 0;
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-- 2009
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SELECT sum(visits) AS visits_2009
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FROM pls_fy2009_pupld09a
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WHERE visits >= 0;
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-- Listing 8-12: Using sum() to total visits on joined 2014 and 2009 library tables
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SELECT sum(pls14.visits) AS visits_2014,
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sum(pls09.visits) AS visits_2009
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FROM pls_fy2014_pupld14a pls14 JOIN pls_fy2009_pupld09a pls09
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ON pls14.fscskey = pls09.fscskey
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WHERE pls14.visits >= 0 AND pls09.visits >= 0;
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-- Listing 8-13: Using GROUP BY to track percent change in library visits by state
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SELECT pls14.stabr,
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sum(pls14.visits) AS visits_2014,
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sum(pls09.visits) AS visits_2009,
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round( (CAST(sum(pls14.visits) AS decimal(10,1)) - sum(pls09.visits)) /
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sum(pls09.visits) * 100, 2 ) AS pct_change
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FROM pls_fy2014_pupld14a pls14 JOIN pls_fy2009_pupld09a pls09
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ON pls14.fscskey = pls09.fscskey
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WHERE pls14.visits >= 0 AND pls09.visits >= 0
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GROUP BY pls14.stabr
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ORDER BY pct_change DESC;
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-- Listing 8-14: Using HAVING to filter the results of an aggregate query
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SELECT pls14.stabr,
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sum(pls14.visits) AS visits_2014,
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sum(pls09.visits) AS visits_2009,
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round( (CAST(sum(pls14.visits) AS decimal(10,1)) - sum(pls09.visits)) /
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sum(pls09.visits) * 100, 2 ) AS pct_change
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FROM pls_fy2014_pupld14a pls14 JOIN pls_fy2009_pupld09a pls09
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ON pls14.fscskey = pls09.fscskey
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WHERE pls14.visits >= 0 AND pls09.visits >= 0
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GROUP BY pls14.stabr
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HAVING sum(pls14.visits) > 50000000
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ORDER BY pct_change DESC;
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