60 lines
1.3 KiB
SQL
60 lines
1.3 KiB
SQL
SELECT COUNT(*)
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FROM subzones
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WHERE population > 15000;
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SELECT max_floor, COUNT(max_floor)
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FROM hdb_blocks
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GROUP BY max_floor
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ORDER BY COUNT(max_floor) desc
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LIMIT 1;
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SELECT *
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FROM areas a
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WHERE region = 'central'
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AND NOT EXISTS (
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SELECT 1
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FROM mrt_stations m,subzones s
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WHERE m.subzone = s.name
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AND s.area = a.name
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);
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SELECT sz.area, COUNT(stop.code) AS num_stops
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FROM mrt_stops stop,
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mrt_stations s,
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subzones sz
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WHERE stop.station = s.name
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AND s.subzone = sz.name
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GROUP BY sz.area
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ORDER BY num_stops DESC
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LIMIT 3;
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SELECT DISTINCT m1.station
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FROM mrt_connections c, mrt_stops m1, mrt_stops m2
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WHERE c.from_code = m1.code
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AND c.to_code = m2.code
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AND m1.line = 'ew'
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AND m2.line != 'ew';
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SELECT sz.area, COUNT(DISTINCT so.line) AS num_lines
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FROM mrt_stops so,
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mrt_stations st,
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subzones sz
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WHERE so.station = st.name
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AND st.subzone = sz.name
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GROUP BY sz.area
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HAVING COUNT(DISTINCT so.line) >= 3
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ORDER BY num_lines DESC;
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SELECT tab.area, COUNT(*) AS num_lines
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FROM (
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SELECT s.area, h.line
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FROM mrt_stops h,
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mrt_stations m,
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subzones s
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WHERE h.station = m.name
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AND m.subzone = s.name
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GROUP BY s.area, h.line
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) tab
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GROUP BY tab.area
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HAVING COUNT (*) >= 3 ORDER BY num_lines DESC |