[英]SQL how do I Check to see if row has that data in table with on a specific grade, and if it does put a Y in another table with that field name
你好这是我的问题,
只需从表 1 中取出 2 列,然后比较等级,以及 CHEM 字段中存在的元素,然后如果它存在于相应的元素字段中,则将其放置为 Y。 我不知道如何在 SQL 中做,下面是一个例子。
在 SQL 中:
表格1:
年级 | 化学 |
---|---|
A30134 | AL |
AS0134 | CR |
AS3021 | 摩 |
AS3011 | CR |
表 2:
年级 | AL | CR | 摩 |
---|---|---|---|
A30134 | 是 | 是 | |
AS3021 | 是 | ||
AS3011 | 是 |
所以基本上,只需从表 1 中取出 2 列,比较等级,以及 CHEM 字段中存在的元素,然后如果它存在于相应的元素字段中,则将其放置为 Y。
UPDATE Table1 INNER JOIN
Table2
(ON Table1.Grade = Table2.Grade) AND (ON I'm not sure how I indicate check field compared to a data cell)
SET Table1.AL = Y;
也许最简单的方法是相关子查询:
UPDATE Table1
SET Table1.AL = IIF(EXISTS (SELECT 1 FROM Table2 WHERE Table1.Grade = Table2.Grade AND Table2.Chem = "AL"), "Y", NULL),
Table1.CR = IIF(EXISTS (SELECT 1 FROM Table2 WHERE Table1.Grade = Table2.Grade AND Table2.Chem = "CR"), "Y", NULL),
Table1.MO = IIF(EXISTS (SELECT 1 FROM Table2 WHERE Table1.Grade = Table2.Grade AND Table2.Chem = "MO"), "Y", NULL);
根据您的示例,您可以尝试以下SQL
。
UPDATE Table1 INNER JOIN Table2 ON Table1.Grade = Table2.Grade SET
Table2.AL = IIf(DCount("[Grade]","[Table1]","[Grade]='" & table2.Grade & "' AND [Chem]='AL'")>0,"Y",Null),
Table2.CR = IIf(DCount("[Grade]","[Table1]","[Grade]='" & [table2].[Grade] & "' AND [Chem]='CR'")>0,"Y",Null),
Table2.MO = IIf(DCount("[Grade]","[Table1]","[Grade]='" & [table2].[Grade] & "' AND [Chem]='MO'")>0,"Y",Null);
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