Question

我有两个表（A和B），其中我想要选择满足条件的两行：

if a.time and b.time <= 12 hours 
AND A.col1 = B.col2 AND A.col2 = B.col1

A

  |Date    | Time  | Col1 | Col2
  |20150818| 000256| AAAA | BBBB
  |20150818| 000456| AAAA | CCCC

乙

  |Date    | Time  | Col1 | Col2
  |20150820| 000359| BBBB | AAAA
  |20150818| 000259| BBBB | AAAA
  |20150818| 001459| CCCC | AAAA

预期输出

  |Date    | Time  | Col1 | Col2 |Date    | Time  | Col1 | Col2
  |20150818| 000256| AAAA | BBBB |20150818| 000259| BBBB | AAAA
  |20150818| 000456| AAAA | CCCC |20150818| 001459| CCCC | AAAA

因为我是SQL新手，

select * 
from A 
where exists 
      (select 1 from B where B.Col1 = A.Col2 and B.Col2 = A.Col1)

仅显示表A中的行而不考虑时间。

Answer 1

为了将一个表的记录与另一个表的记录组合在一起，您加入表：

当您将日期和时间存储为字符串时，必须先将它们转换为DATE（即日期时间值）。然后从另一个中减去一个，以便得到天数的差异。 12小时= 0.5天。

select 
  a.date, a.time, a.col1, a.col2,
  b.date, b.time, b.col1, b.col2
from a
join b on a.col1 = b.col2 and a.col2 = b.col1
 and abs(to_date(a.date || a.time , 'yyyymmddhh24miss') -
         to_date(b.date || b.time , 'yyyymmddhh24miss')) <= 0.5;

将日期和时间存储在两个单独的varchar列中的方式并不常见。通常，您只需使用包含日期和时间的DATE列。

Answer 2

SQL Fiddle

Oracle 11g R2架构设置：

CREATE TABLE A ( "Date", "Time", Col1, Col2 ) AS
          SELECT '20150818', '000256', 'AAAA', 'BBBB' FROM DUAL
UNION ALL SELECT '20150818', '000456', 'AAAA', 'CCCC' FROM DUAL;

CREATE TABLE B ( "Date", "Time", Col1, Col2 ) AS
          SELECT '20150820', '000359', 'BBBB', 'AAAA' FROM DUAL
UNION ALL SELECT '20150818', '000259', 'BBBB', 'AAAA' FROM DUAL
UNION ALL SELECT '20150818', '001459', 'CCCC', 'AAAA' FROM DUAL;

查询1 ：

SELECT *
FROM   A
       INNER JOIN
       B
       ON (
             TO_DATE( a."Date" || a."Time", 'YYYYMMDDHH24MISS' ) BETWEEN TO_DATE( b."Date" || b."Time", 'YYYYMMDDHH24MISS' ) - INTERVAL '12' HOUR AND TO_DATE( b."Date" || b."Time", 'YYYYMMDDHH24MISS' ) + INTERVAL '12' HOUR
         AND a.Col1 = b.Col2
         AND a.Col2 = b.Col1
       )

<强> Results ：

|     Date |   Time | COL1 | COL2 |     Date |   Time | COL1 | COL2 |
|----------|--------|------|------|----------|--------|------|------|
| 20150818 | 000256 | AAAA | BBBB | 20150818 | 000259 | BBBB | AAAA |
| 20150818 | 000456 | AAAA | CCCC | 20150818 | 001459 | CCCC | AAAA |

Answer 3

试试这个

select * from A inner join (select * from B where b.time <= 12 hours) C
on  C.Col1 = A.Col2 and C.Col2 = A.Col1

检查另一个表中是否存在列 - SQL

3 个答案: