Php mysql bad query when displays on a table

Question

there's my code that select 5 databases and display in a table, but the where statement not work

The where is ignored by the query.

SELECT *
FROM events
UNION ALL
SELECT * FROM eventstwo
UNION ALL
SELECT * FROM eventsthree
UNION ALL
SELECT * FROM eventsfour
UNION ALL
SELECT * FROM eventsfive where atender='$obj'

"not work" is a completely unhelpful description. What's it supposed to do? What's it actually do? — Joseph Sible-Reinstate Monica
– Joseph Sible-Reinstate Monica, Commented Oct 11, 2018 at 3:27
Do you have a column named as "atender" and any row in the column has "$obj" as data? — TejSoft
– TejSoft, Commented Oct 11, 2018 at 4:02

Tim Biegeleisen · Accepted Answer · 2018-10-11 03:42:15Z

1

I suspect that you want the WHERE criteria to apply to every subquery in the union. If you want that, you'll have to add a WHERE clause to each subquery. But, if you really do want to use a single WHERE clause, you can wrap your union query and then subquery it:

SELECT *
FROM
(
    SELECT * FROM events
    UNION ALL
    SELECT * FROM eventstwo
    UNION ALL
    SELECT * FROM eventsthree
    UNION ALL
    SELECT * FROM eventsfour
    UNION ALL
    SELECT * FROM eventsfive
) t
WHERE atender = '$obj';

Side note: Please use prepared statements in your PHP code wherever possible.

answered Oct 11, 2018 at 3:42

Tim Biegeleisen

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1 Comment

Nebulacrypt Over a year ago

Yep and now i use prepared statements but im new with the unions, thank you for the help tim.

김라댜 · Accepted Answer · 2018-10-11 03:42:55Z

1

SELECT * FROM
              ( SELECT *
                FROM events
                UNION ALL
                SELECT * FROM eventstwo
                UNION ALL
                SELECT * FROM eventsthree
                UNION ALL
                SELECT * FROM eventsfour
                UNION ALL
                SELECT * FROM eventsfive)
                  AS derived
WHERE atender='$obj'

answered Oct 11, 2018 at 3:42

김라댜

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