Access幾個小技巧總結
1、查詢Access中的表名稱
select name from MSysObjects where type=1 and flags=0 MSysObjects
2、幾個查詢結果Union All時,當使用了無表查詢時,提示“查詢輸入必須包含至少一個表或查詢”
也就是說在Access裏,這樣的查詢,並不能出想要的結果
select 'wallimn'
union all
select name from MSysObjects
這時可以建一個一行一列的表,比如效仿Oracle,建一個DUAL,從這個表裏查些不相干的東西就行了。
select 'wallimn' from dual
union all
select name from MSysObjects
3、Access多表外聯查詢(三個或以上)的寫法
SELECT * FROM (aa LEFT JOIN bb ON aa.a = bb.a ) LEFT JOIN cc ON cc.a = bb.a;
注意:在使用join語句查詢時,如果有加多個On條件,必須用括號括起來,如:
SELECT * FROM (aa LEFT JOIN bb ON aa.a=bb.a) LEFT JOIN cc ON(bb.a=cc.a and bb.b=cc.b)
其他例子可以參考:
(1)、SELECT * FROM URL as a LEFT OUTER JOIN MobileAfter as b ON a.URL = b.URL
(2)、SELECT * FROM (URL as a LEFT OUTER JOIN MobileAfter as b ON a.URL= b.URL) LEFT OUTER JOIN MobileBefore as c ONc.URL=a.URL
(3)、SELECT * INTO Ttable1 FROM ((((URL as a
LEFT OUTER JOIN MobileAfter as b ON a.URL=b.URL)
LEFT OUTER JOIN MobileBefore as c ON c.URL=a.URL)
LEFT OUTER JOIN TeleCOM as d ON d.URL=a.URL)
LEFT OUTER JOIN UniCOM as e ON e.URL=a.URL)
select name from MSysObjects where type=1 and flags=0 MSysObjects
2、幾個查詢結果Union All時,當使用了無表查詢時,提示“查詢輸入必須包含至少一個表或查詢”
也就是說在Access裏,這樣的查詢,並不能出想要的結果
select 'wallimn'
union all
select name from MSysObjects
這時可以建一個一行一列的表,比如效仿Oracle,建一個DUAL,從這個表裏查些不相干的東西就行了。
select 'wallimn' from dual
union all
select name from MSysObjects
3、Access多表外聯查詢(三個或以上)的寫法
SELECT * FROM (aa LEFT JOIN bb ON aa.a = bb.a ) LEFT JOIN cc ON cc.a = bb.a;
注意:在使用join語句查詢時,如果有加多個On條件,必須用括號括起來,如:
SELECT * FROM (aa LEFT JOIN bb ON aa.a=bb.a) LEFT JOIN cc ON(bb.a=cc.a and bb.b=cc.b)
其他例子可以參考:
(1)、SELECT * FROM URL as a LEFT OUTER JOIN MobileAfter as b ON a.URL = b.URL
(2)、SELECT * FROM (URL as a LEFT OUTER JOIN MobileAfter as b ON a.URL= b.URL) LEFT OUTER JOIN MobileBefore as c ONc.URL=a.URL
(3)、SELECT * INTO Ttable1 FROM ((((URL as a
LEFT OUTER JOIN MobileAfter as b ON a.URL=b.URL)
LEFT OUTER JOIN MobileBefore as c ON c.URL=a.URL)
LEFT OUTER JOIN TeleCOM as d ON d.URL=a.URL)
LEFT OUTER JOIN UniCOM as e ON e.URL=a.URL)
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