如何在postgresql中忽略select distinct的列？

大家好！

我有一个sql(见上文),我想知道我怎么能确保我不会得到关于名称的双打.如果名称出现在第一个中选择它是主要名称,则应在以下选择中忽略.

"SELECT name,id,'place' AS tablename FROM places WHERE lower(name) LIKE '".strtolower($needle)."%'"
    ."UNION SELECT name,'community' AS tablename FROM communities WHERE lower(name) LIKE '".strtolower($needle)."%'"
    ."UNION SELECT name,'district' AS tablename FROM districts WHERE lower(name) LIKE '".strtolower($needle)."%'"
    ."UNION SELECT name,'region' AS tablename FROM regions WHERE lower(name) LIKE '".strtolower($needle)."%'"
    ."UNION SELECT name,'province' AS tablename FROM provinces WHERE lower(name) LIKE '".strtolower($needle)."%'"
    ."ORDER BY name LIMIT 10"

这是我的sql.

你需要更多信息吗？

谢谢

DISTINCT

SELECT disTINCT ON (name) name,tablename 
FROM (
    SELECT name,'place' AS ... 
    UNION ... 
    UNION ... 
    UNION ... 
    UNION ...) AS subQuery
ORDER BY name LIMIT 10

只需通过将查询用作子查询,指定仅对名称执行不同的操作.

在不同的期间执行限制和排序,否则不同的可能会丢弃欺骗并且不以正确的排序顺序放弃完整的10行.