[英]My MySQL SELECT Query is Returning Multiples of the Same Rows
由于某种原因,我只能看到一个重复的行,但无法真正查明查询中我哪里出错了。
$stmt = $mysqli->query("
SELECT DISTINCT vendors_tbl.email AS email,
(vendor_avails_tbl.standard_pricing - vendor_loc_tbl.offpeak_time_pricing) AS best_margins,
vendor_loc_tbl.location_id AS locationID,
vendor_loc_tbl.loc_img_path AS locImg,
vendor_loc_tbl.offpeak_time_pricing AS offpeak,
vendor_loc_tbl.address1 AS address1,
vendor_loc_tbl.address2 AS address2,
vendor_loc_tbl.zip_code AS zip,
vendor_loc_tbl.geocodes AS geo,
vendor_loc_tbl.has_valet AS valet,
vendor_loc_tbl.has_transport AS transport,
vendor_loc_tbl.has_wheelchair AS wheelchair,
vendor_loc_tbl.has_desk AS desk,
vendor_loc_tbl.has_24hours AS open24hrs,
vendor_loc_tbl.has_covered AS covered,
vendor_loc_tbl.has_security AS security,
(vendor_avails_tbl.available_economy + vendor_avails_tbl.available_standard + vendor_avails_tbl.available_midsize + vendor_avails_tbl.available_truck_suv) AS avail_total,
vendor_avails_tbl.standard_pricing AS standard_pricing, 69 *
DEGREES(ACOS(COS(RADIANS($e_lat))
* COS(RADIANS(SUBSTR(vendor_loc_tbl.geocodes, 1, 10)))
* COS(RADIANS($e_lon) - RADIANS(SUBSTR(vendor_loc_tbl.geocodes, 13)))
+ SIN(RADIANS($e_lat))
* SIN(RADIANS(SUBSTR(vendor_loc_tbl.geocodes, 1, 10))))) AS distance_in_m
FROM vendors_tbl
INNER JOIN vendor_loc_tbl ON vendor_loc_tbl.vendor_id = vendors_tbl.vendor_id
INNER JOIN vendor_avails_tbl ON vendor_avails_tbl.location_id = vendor_loc_tbl.location_id
WHERE vendor_avails_tbl.available_standard > 0
ORDER BY vendor_loc_tbl.override_level DESC, best_margins DESC, distance_in_m ASC
LIMIT 5
");
在某些情况下,最好使用GROUP BY
语句而不是DISTINCT
。 在您的示例中,您应至少在一个栏上添加一个组(例如ID的某些唯一名称)。 当您在查询中使用聚合时,最好仅在使用联接时使用分组方式-单独就足够了。
由于您没有按条件指定分组,因此您可以创建已指定的所有字段的分组。 因此,没有机会获得重复的价值。
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