在 PostgreSQL 中，DISTINCT 关键字与 SELECT 语句一起使用，用于去除重复记录，只获取唯一的记录。

我们平时在操作数据时，有可能出现一种情况，在一个表中有多个重复的记录，当提取这样的记录时，DISTINCT 关键字就显得特别有意义，它只获取唯一一次记录，而不是获取重复记录。

语法
用于去除重复记录的 DISTINCT 关键字的基本语法如下：

SELECT DISTINCT column1, column2,.....columnN
FROM table_name
WHERE [condition]
实例
创建 COMPANY 表（下载 COMPANY SQL 文件 ），数据内容如下：
http://m.douguo.com/recipe/amp/2906302
http://m.douguo.com/recipe/mip/2906302
http://m.douguo.com/recipe/amp/2906461
http://m.douguo.com/recipe/mip/2906461
http://m.douguo.com/recipe/amp/2906473
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http://m.douguo.com/recipe/amp/2906519
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http://m.douguo.com/recipe/mip/2906537
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http://m.douguo.com/recipe/mip/2906608
http://m.douguo.com/recipe/amp/2906633
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http://m.douguo.com/recipe/mip/2906712
http://m.douguo.com/recipe/amp/2906745
http://m.douguo.com/recipe/mip/2906745
http://m.douguo.com/recipe/amp/2906751
http://m.douguo.com/recipe/mip/2906751
http://m.douguo.com/recipe/amp/2906763
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http://m.douguo.com/recipe/mip/2906782
http://m.douguo.com/recipe/amp/2906803
http://m.douguo.com/recipe/mip/2906803
http://m.douguo.com/recipe/amp/2906839
http://m.douguo.com/recipe/mip/2906839
http://m.douguo.com/recipe/amp/2906884
http://m.douguo.com/recipe/mip/2906884
http://m.douguo.com/recipe/amp/2906890
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http://m.douguo.com/recipe/mip/2906888
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http://m.douguo.com/recipe/amp/2906965
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http://m.douguo.com/recipe/amp/2907047
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http://m.douguo.com/recipe/amp/2907369
http://m.douguo.com/recipe/mip/2907369
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http://m.douguo.com/recipe/amp/2907446
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http://m.douguo.com/recipe/amp/2907631
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http://m.douguo.com/recipe/amp/2907632
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http://m.douguo.com/recipe/amp/2907635
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http://m.douguo.com/recipe/amp/2907660
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http://m.douguo.com/recipe/amp/2907665
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http://m.douguo.com/recipe/amp/2908122
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http://m.douguo.com/recipe/amp/2906338
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http://m.douguo.com/recipe/amp/2906363
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http://m.douguo.com/recipe/amp/2906411
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http://m.douguo.com/recipe/amp/2906562
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http://m.douguo.com/recipe/amp/2906578
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http://m.douguo.com/recipe/amp/2906579
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http://m.douguo.com/recipe/amp/2906580
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http://m.douguo.com/recipe/amp/2906596
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http://m.douguo.com/recipe/amp/2906610
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http://m.douguo.com/recipe/amp/2906798
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http://m.douguo.com/recipe/amp/2906813
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http://m.douguo.com/recipe/amp/2907079
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http://m.douguo.com/recipe/amp/2907130
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http://m.douguo.com/recipe/amp/2907325
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http://m.douguo.com/recipe/amp/2907365
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http://m.douguo.com/recipe/amp/2907432
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http://m.douguo.com/recipe/amp/2907447
http://m.douguo.com/recipe/mip/2907447
http://m.douguo.com/recipe/amp/2907476
http://m.douguo.com/recipe/mip/2907476
http://m.douguo.com/recipe/amp/2907528
http://m.douguo.com/recipe/mip/2907528
http://m.douguo.com/recipe/amp/2907750
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http://m.douguo.com/recipe/amp/2908054
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