Question

你好，

我在这里遇到了问题。我正在开发搜索选项。我可以搜索名字，姓氏，公司名称和车牌。我只想显示左侧，也是客户信息，我通过以下查询获得。但是，如果客户没有铭牌，则不会显示客户。有没有办法防止这种情况？

SELECT DISTINCT A.* 
FROM adressen AS A 
OUTER JOIN fahrzeuge AS F 
ON F.fa_kunden_id = A.ad_id 
WHERE CONCAT(coalesce(A.ad_name), coalesce(A.ad_vorname),coalesce(A.ad_firma), coalesce(F.fa_kennzeichen)) LIKE '%"+wndHauptfenster.textfield_suche.Text+"%'

我也尝试过使用IFNULL，但这会导致'无结果'，即使对于有车的客户也是如此：

SELECT DISTINCT A.* 
FROM adressen AS A 
OUTER JOIN fahrzeuge AS F 
ON F.fa_kunden_id = A.ad_id 
WHERE CONCAT(coalesce(A.ad_name), coalesce(A.ad_vorname),coalesce(A.ad_firma), coalesce(ifnull(F.fa_kennzeichen, 'leer'))) LIKE '%"+wndHauptfenster.textfield_suche.Text+"%'

更新：尝试给定的解决方案后，根本找不到任何内容。

SELECT DISTINCT A.* 
FROM adressen AS A 
OUTER JOIN fahrzeuge AS F 
ON F.fa_kunden_id = A.ad_id 
WHERE CONCAT(coalesce(A.ad_name, ''), coalesce(A.ad_vorname, ''),coalesce(A.ad_firma, ''), coalesce(F.fa_kennzeichen, '')) LIKE '%"+wndHauptfenster.textfield_suche.Text+"%'

Adressen中的专栏：

ad_vorname包含Max
ad_name包含Mustermann
ad_firma包含Testfirma Inc
fa_kennzeichen什么都没有。查询正在搜索的行不存在。

Answer 1

怎么样：

SELECT DISTINCT A.* 
FROM adressen AS A 
OUTER JOIN fahrzeuge AS F 
ON F.fa_kunden_id = A.ad_id 
WHERE CONCAT(coalesce(A.ad_name,''), coalesce(A.ad_vorname,''),coalesce(A.ad_firma,''), coalesce(F.fa_kennzeichen,'')) LIKE '%"+wndHauptfenster.textfield_suche.Text+"%'

Answer 2

OUTER JOIN是语法错误。应为LEFT OUTER JOIN，或缩写为LEFT JOIN。

SELECT DISTINCT A.* 
FROM adressen AS A 
LEFT OUTER JOIN fahrzeuge AS F 
ON F.fa_kunden_id = A.ad_id 
WHERE CONCAT(coalesce(A.ad_name, ''), coalesce(A.ad_vorname, ''),coalesce(A.ad_firma, ''), coalesce(F.fa_kennzeichen, '')) LIKE '%"+wndHauptfenster.textfield_suche.Text+"%'

查询：加入，Concat，但获得结果

2 个答案: