如何用一个查询搜索多个词？

Question

I am trying to make a simple php search using the following query. This works perfectly however the query only gives results for the first word. Would there be a way to get a combined result for all three words using a single query?

$stmt = $pdo->prepare("SELECT * FROM walldb WHERE (wallname LIKE :searchq1 OR :searchq2 OR :searchq3) LIMIT :stat, :limt");

Answer 1

You need to repeat the expr like val pattern:

WHERE wallname LIKE :searchq1 OR wallname LIKE :searchq2 OR wallname LIKE :searchq3

What happends with your original code is that it is interpreted as:

WHERE 
    (wallname LIKE :searchq1)
    OR (:searchq2)
    OR (:searchq3)

So basically the last two search terms are evaluated in boolean context, as if they were conditions. If one of the search terms starts with 1 , it is evaluated as true (and all rows in the table will be returned); else if neither starts with 1 , the conditions are false, hence only the first condition comes into play (which is what you are seeing).

Answer 2

You cannot use OR in the way you show. :searchq2 is not a valid where expression. You need to do the following:

wallname LIKE :searchq1 OR wallname LIKE :searchq2 OR wallname LIKE :searchq3

Answer 3

You might want to consider regular expressions. You could express what you want as:

where wallname regexp concat('^', concat_ws('|', :searchq1, :searchq2, :searchq3), '$')

assuming that the parameters do not have special characters in them.

However, perhaps you should consider one regular expression. Then you could express the condition as:

where allname regexp '^abc|def|ghi$')

Answer 4

If You want to decrease query execution time, use UNION ALL (as many parts to union as 'OR' appearences). Otherwise (transparent and short script) use all conditions in one line - as above.