MySQL支持多种数据类型之间的转换,主要包括: 字符串(CHAR、VARCHAR、TEXT等) 数字(INT、FLOAT、DECIMAL等) 日期/时间(DATE、TIME、DATETIME等) 二进制数据(BINARY、VARBINARY等) 优势 灵活性:CAST函数允许你在查询中动态地转换数据类型,这在处理不同数据源或合并不同数据表时非常有
BINARY) syntax. // To restore old behavior just remove this "if ($3...)" branch. $$.charset= get_bin_collation($3.charset ? $3.charset : YYTHD->variables.collation_connection); if ($$.charset == nullptr) MYSQL_YYABORT; } else $$.charset= $3.charset; } | nchar opt_...
MySQL中的CAST函数用于将一个数据类型转换为另一个数据类型。它允许你在查询中对数据进行类型转换,以便进行比较、计算或其他操作。 语法 代码语言:txt 复制 CAST(expression AS type) expression:要转换的表达式。 type:目标数据类型。 支持的数据类型 BINARY[(N)] ...
To convert strings between character sets, you can also useCONVERT(expr,type)syntax (withoutUSING), orCAST(exprAStype), which is equivalent: CONVERT(string,CHAR[(N)]CHARACTERSETcharset_name)CAST(stringASCHAR[(N)]CHARACTERSETcharset_name)
Why not see decimal in output `result` ? Is not sufficient the round syntax? thank you. mysql> SELECT ID, AV, ROUND( CAST( REPLACE (AV, ".", "") AS DECIMAL (10, 2) ), 2 ) AS result FROM tbl_m WHERE ID = 833; +---+---+---+ | ID | av | result | +---+--...
MySQL 源码|65 - 语法解析(V2):字符串字面值 在基础表达式语义组 simple_expr 中,直接规定了类型转换函数 CAST、CONVERT 和关键字 BINARY 引导的类型转换语法的备选规则,这 3 个函数官方文档和标准语法详见 MySQL 参考手册 - 14.10 Cast Functions and Operators。在梳理 simple_expr 语义组之前,我们先来梳理这 ...
Regardless of the syntax used, the function returns NULL if expr is NULL. CONVERT(expr USING transcoding_name) converts data between different character sets. In MySQL, transcoding names are the same as the corresponding character set names. For example, this statement converts the string 'abc...
The CAST() function takes an expression of any type and produces a result value of the specified type, similar to CONVERT(). For more information, see the description of CONVERT(). CAST() is standard SQL syntax. 文档创建时间:2018年6月26日15:38:27...
Syntax error converting the varchar value '12.5' to a column of data type int. (4). 要返回一个合法的数值,就必须使用能处理这个值的数据类型。对于这个例子,存在多个可用的数据类型。如果通过CAST()函数将这个值转换为 decimal类型,需要首先定义decimal值的精度与小数位数。在本例中,精度与小数位数分别为9...
Syntax CAST(expr AS type_name) Arguments expr can be an expression in one of the data types. type_name is one of the data types listed in Table1-2,"Dimensional Data Types". Table 3-1 shows which data types can be cast into which other built-in data types. NUMBER includes NUMBER, ...