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rugenhankeys
Starting Member
1 Post |
 Posted - 2014-08-29 : 08:07:14
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| HiJust need a little help as new to SQL.I have a table which contains readingtime (records every 4 seconds during the day) and an energy reading. I wanted to know how much energy was used in a day. this is the query that i usedSELECT date(readingtime), max(energy)-min(energy)as total FROM lights_1 WHERE readingtime between 20140407000000 and 20140409235959 Group by date(readingtime) LIMIT 0,30;This gave me the desired results for 1 table. I have 4 tables of these lights_2, Lights_3, lights_4 and i would like to display them together and hence match up the reading time so each day has the energy requirements for all for tables with the total. When i try and join tables i get a lot of errors!Can anyone help.thanks |
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gbritton
Master Smack Fu Yak Hacker
2780 Posts |
Posted - 2014-08-29 : 09:50:43
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| Post the code you are using to display all four tables together. |
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calculating data from multiple tables