SUBSTRING (value_expression ,start_expression ,length_expression ) 参数 value_expression 是character、binary、text、ntext 或 image表达式。 start_expression 指定返回字符的起始位置的整数或 bigint 表达式。如果 start_expression 小于 1,则返回的表达式的起始位置为 value_expression 中指定的第一个字符。在这种...
DECLARE n integer DEFAULT 0; WHILE n < 10 do SET n = n + 1 END WHILE REPEAT SET n = n – 1 UNTIL n = 0 END REPEAT --- /* 查找位于Watson大楼的所有院系的budget总和, 其中n是局部变量,初始化为0,for循环执行查询,并做累加计算 */ --for循环,对查询到的所有结果重复执行 DE...
A. Use SUBSTRING with a character string The following example shows how to return only a part of a character string. From thesys.databasestable, this query returns the system database names in the first column, the first letter of the database in the second column, and the third and fou...
'abc'SIMILAR TO'abc'true'abc'SIMILAR TO'a'false'abc'SIMILAR TO'%(b|d)%'true'abc'SIMILAR TO'(b|c)%'false 带三个参数的substring,即substring(string from pattern for escape-character),提供了抽取一个匹配 SQL 正则表达式的子串的方法。和SIMILAR TO一样,声明的模式必须匹配整个数据串,否则函数失败...
SET @position = 1; SET @string = 'New Moon'; WHILE @position <= DATALENGTH(@string) BEGIN SELECT ASCII(SUBSTRING(@string, @position, 1)), CHAR(ASCII(SUBSTRING(@string, @position, 1))) SET @position = @position + 1 END; GO 結果集如下所示。輸出...
extract string between two characters/string, first character is 'Test Name:' and second character is line break i.e., or end of line. Extracting domain name from FQDN fully qualified domain name see example Extracting only year from getdate() function... Extracting substring between two ch...
substring_matches json JSON document describing match. Examples Return tabular results from 'Learning #AzureSQL #AzureSQLDB' that start with a # character followed by one or more alphanumeric characters (A-Z, a-z, 0-9) or underscores (_). SQL Kopija SELECT * FROM REGEXP_MATCHES('Learnin...
substring(String str, Int start [, Int len]) String 返回原字符串从 start 位置开始,长度为 len 的子串。start 从 1 开始,支持负数,此时从结尾开始反向计算位置。len 参数不传表示截取到字符串结尾 >select substr("fOoBaR", 2, 4)OoBa>select substr("fOoBaR", -3, 2)Ba substr(String str, Int st...
This will tell Oracle SQL to start at the second character from the end of the string (the last “l” in “seashells”) and search forward until it finds the 5th instance of “s” — in this case, the first letter of “she”, which will return 1. ...
substring 非保留(不能是函数或 非保留 保留 类型) sum - 非保留 保留 superuser 非保留 - - symmetric 保留 非保留 - synonym 非保留 - - sys_refcursor 非保留 - - sysdate 保留 - - sysid 非保留 - - system 非保留 非保留 - system_user - 保留 保留 table 保留 保留 保留 tables 非保留 - -...