Show the name and the capital where the first letters of each match. Don't include countries where the name and the capital are the same word. You can use the functionLEFTto isolate the first character. You can use<>as theNOT EQUALSoperator. SELECT name,capital FROM world WHERE LEFT(name...
Structured Query Language (SQL) is a programming language that has several commands, operators and functions. SQL Is said to be the best in maintaining efficient database systems. You can create data, duplicate data, store data, clear the unnecessary data and do many other functions using SQL....
WHERE A operator B 练习:查询超过 20 岁的教师。select * from teachers where age > 20; 2.逻辑运算符:AND、OR、NOT ① 使用AND连接多条件: 使用SQL 中的逻辑运算符 AND 可以将 WHERE 子句中将两个或两个以上的条件结合起来,其结果是满足 AND 连接的所有条件的数据。 语法: SELECT `column_name` FROM...
WHERE A operator B 练习:查询超过 20 岁的教师。select * from teachers where age > 20; 2.逻辑运算符:AND、OR、NOT ① 使用AND连接多条件: 使用SQL 中的逻辑运算符 AND 可以将 WHERE 子句中将两个或两个以上的条件结合起来,其结果是满足 AND 连接的所有条件的数据。 语法: SELECT `column_name` FROM...
在SQL 语句使用过程中,经常会碰到NULL 这几个字符。通常使用 NULL 来表示缺失的值,也就是在表中该字段是没有值的。如果在创建表时,限制某些字段不为空,则可以使用NOT NULL关键字,不使用则默认可以为空。在向表内插入记录或者更新记录时,如果该字段没有NOT NULL并且没有值,这时候新记录的该字段将被保存为 NUL...
The LIKE operator in SQL is used with the WHERE clause to check if a value matches a given string. In this tutorial, we'll learn about the LIKE clause in SQL and how to use them with examples.
The SQL LIKE operator is only applied on a field of types CHAR or VARCHAR to match a pattern. To match a pattern from a word, special characters, and wildcards characters may have used with LIKE operator. The LIKE operator can be used within any valid SQL statement, such as SELECT, ...
Any wildcard, like%and_, can be used in combination with other wildcards. Example Return all customers that starts with "a" and are at least 3 characters in length: SELECT*FROMCustomers WHERECustomerNameLIKE'a__%'; Try it Yourself » ...
Operator IN is used to include only values from the list. You can use the operator for all data types, such as numbers or strings. [C#] dataView.RowFilter = "Id IN (1, 2, 3)" // integer values dataView.RowFilter = "Price IN (1.0, 9.9, 11.5)" // float values dataView.RowFilte...
例如,如果在 SQL 查询中输入 Like "C*" ,该查询将返回以字母 C 开头的所有字段值。在参数查询中,可以提示用户输入要搜索的模式。 以下示例返回以字母 P 开头并且后面为 A 到 F 之间任何字母和三个数字的数据: VB 复制 Like "P[A-F]###" 下表演示如何使用 Like 来测试不同模式的表达式。 ...