簡單凡在SQL

Question

我有一臺X和Y

表X

a 
b 
c 
d 

數據表Y

a 1 1 
a 32 5 
b 1 1 
b 4 5 
c 5 65 

我想在輸出c和d，因爲他們沒有在表Y值爲1的記錄1

我該如何得到它？

Answer 1

你不給任何列名，所以我做了一些！

SELECT col1 
FROM tablex 
EXCEPT 
select col1 
FROM tabley 
WHERE col2=1 and col3=1 

如果過於簡化的例子，確實需要額外的列從tablex使用NOT EXISTS

SELECT tablex.* 
FROM tablex 
WHERE NOT EXISTS (SELECT * 
        FROM tabley 
        WHERE col2 = 1 
          AND col3 = 1 
          AND tablex.col1 = tabley.col1) 

Answer 2

我想我明白：

SELECT X.column FROM X 
WHERE X.column NOT IN 
(SELECT Y.column FROM Y WHERE Y.column2=1 AND Y.column3=1) 

Answer 3

SELECT col1 
FROM TableX 
WHERE col1 
NOT IN (select col1 
FROM TableY 
WHERE col2=1 and col3=1)