早上好社区,当我从 SQL 2018 运行此查询时遇到问题,Visual Basic 2010 向我显示以下错误“已添加具有相同键的元素”
SELECT DESCRIPCION AS nodeText,'DEPA' + CAST(IDDEPARTAMENTO AS VARCHAR) AS nodeKey,''AS nodeParentKey FROM DEPARTAMENTO
UNION ALL
SELECT DESCRIPCION AS nodeText,'PROV' + CAST(IDPROVINCIA AS VARCHAR) AS nodeKey,
'DEPA' + CAST(IDDEPARTAMENTO AS VARCHAR) AS nodeParentKey FROM PROVINCIA
UNION ALL
SELECT DESCRIPCION AS nodeText,'DIST' + CAST(IDUBIGEO AS VARCHAR) AS nodeKey,
'PROV' + CAST(IDPROVINCIA AS VARCHAR) AS nodeParentKey FROM ubigeo
由于我可以避免重复元素,我认为它是与 DISTINCT 子句,但我不知道这个子句可以去哪里,请支持
以这种方式使用 UNION 而不是 UNION ALL:
它将删除重复项