关注微信公共号：小程在线
关注CSDN博客：程志伟的博客
ClickHouse server version 21.6.6
1.lower函数
将所有字符串转成小写
dblab-VirtualBox :) select lower('ABc');
SELECT lower('ABc')
Query id: f8c4bba3-9296-43fc-a752-cfb7cf3e323c
┌─lower('ABc')─┐
│ abc │
└──────────────┘
1 rows in set. Elapsed: 0.004 sec.
2.upper 函数
将所有字符串转成大写
dblab-VirtualBox :) select upper('ABc');
SELECT upper('ABc')
Query id: 11d47078-721c-474d-a3c9-8a2848213e00
┌─upper('ABc')─┐
│ ABC │
└──────────────┘
1 rows in set. Elapsed: 0.004 sec.
3. repeat 函数
将字符串重复N次
dblab-VirtualBox :) SELECT repeat('abc', 10);
SELECT repeat('abc', 10)
Query id: 88696b97-3501-4d8c-ba4d-73573cd3d746
┌─repeat('abc', 10)──────────────┐
│ abcabcabcabcabcabcabcabcabcabc │
└────────────────────────────────┘
1 rows in set. Elapsed: 0.003 sec.
4. concat函数
拼接函数
dblab-VirtualBox :) SELECT concat('Hello, ', 'World!');
SELECT concat('Hello, ', 'World!')
Query id: 9f936937-6813-436e-af69-f6212d5f0dc4
┌─concat('Hello, ', 'World!')─┐
│ Hello, World! │
└─────────────────────────────┘
1 rows in set. Elapsed: 0.003 sec.
5.mid函数、substring函数
dblab-VirtualBox :) select mid('asdfghjkl',1,2);
SELECT mid('asdfghjkl', 1, 2)
Query id: f73bd993-3966-4bf4-8476-92f66979c98f
┌─substring('asdfghjkl', 1, 2)─┐
│ as │
└──────────────────────────────┘
1 rows in set. Elapsed: 0.006 sec.
6. startsWith函数 字符串是否以指定前缀开头返回1，否则返回0。
dblab-VirtualBox :) SELECT startsWith('Spider-Man', 'Spi');
SELECT startsWith('Spider-Man', 'Spi')
Query id: f4d53309-8b94-4ae7-a75f-e86f5b0cc339
┌─startsWith('Spider-Man', 'Spi')─┐
│ 1 │
└─────────────────────────────────┘
1 rows in set. Elapsed: 0.004 sec.
7.trim函数 去除空格
dblab-VirtualBox :) select trim(' hah ')
SELECT trimBoth(' hah ')
Query id: f86d7254-626f-4d72-80d4-e050e7118ef2
┌─trimBoth(' hah ')─┐
│ hah │
└───────────────────┘
1 rows in set. Elapsed: 0.003 sec.
8.POSITION函数 字符串搜索函数
dblab-VirtualBox :) SELECT POSITION('2121stringstrstrstrstr','str');
SELECT POSITION('2121stringstrstrstrstr', 'str')
Query id: aa333cd0-df02-43da-bfe5-5ab3f2c12a26
┌─position('2121stringstrstrstrstr', 'str')─┐
│ 5 │
└───────────────────────────────────────────┘
1 rows in set. Elapsed: 0.007 sec.
9.match函数 匹配到了则返回1，否则返回0
dblab-VirtualBox :) select match('1232434sadgaDDFSrefds', '[0-9a-zA-Z]');
SELECT match('1232434sadgaDDFSrefds', '[0-9a-zA-Z]')
Query id: fb2d0889-a232-405a-90d8-62456b54db68
┌─match('1232434sadgaDDFSrefds', '[0-9a-zA-Z]')─┐
│ 1 │
└───────────────────────────────────────────────┘
1 rows in set. Elapsed: 0.005 sec.
10.replaceOne、replace函数
dblab-VirtualBox :) select replaceOne('hed1234544', '4', '*');
SELECT replaceOne('hed1234544', '4', '*')
Query id: 1a094472-30a3-4e7d-948e-8d25af0dcd2d
┌─replaceOne('hed1234544', '4', '*')─┐
│ hed123*544 │
└────────────────────────────────────┘
1 rows in set. Elapsed: 0.003 sec.
dblab-VirtualBox :) select replace('hed1234544', '4', '*');
SELECT replace('hed1234544', '4', '*')
Query id: bf593274-668a-4a0c-a20f-7d3913dd907f
┌─replaceAll('hed1234544', '4', '*')─┐
│ hed123*5** │
└────────────────────────────────────┘
1 rows in set. Elapsed: 0.006 sec.