SELECT Data from multiple tables?

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慢半拍i
慢半拍i 2021-01-01 02:55

I have 3 tables, with 3 fields all the same. I basically want to select information from each table

For example:

userid = 1

I want

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  • 2021-01-01 03:24

    with 3 fields all the same

    So you mean that you want the same 3 fields from all 3 tables?

       SELECT r.col1, r.col2, r.col3
         FROM random r
        WHERE r.userid = '1'
        LIMIT 0, 30
    UNION ALL 
       SELECT p.pcol1, p.pcol_2, p.p3
         FROM pandom p
        WHERE p.userid = '1'
        LIMIT 0, 30
    UNION ALL 
       SELECT l.l1, l.l2, l.l3
         FROM landom l
        WHERE l.userid = '1'
        LIMIT 0, 30
    

    The fields don't have to be named the same, but the same types need to line up in position 1, 2 and 3.

    The way the limits work is:

    • it will attempt to get 30 from random.
    • If it has 30 already, it won't even look at the other 2 tables
    • if it has less than 30 from random, it will try to fill up to 30 from pandom and only finally landom
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  • 2021-01-01 03:28
    SELECT * FROM `random`
             JOIN `pandom` USING (`userid`)
             JOIN `landom` USING (`userid`)
    WHERE `userid`='1'
    
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  • 2021-01-01 03:33
    SELECT t1.*, t2.*, t3.* 
       FROM `random` as t1, `pandom` as t2, `landom` as t3 
    WHERE t1.`userid`='1' AND t2.`userid`='1' AND t3.`userid`='1'
    
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