用SELECT语句查询数据表中的记录(最常用的语句) SELECT 语句的语法如下:SELECT selection_list选择哪些列FROM table_list从何处选择行WHERE primary_constraint行必须满足什么条件GROUP BY grouping_columns怎样对结果分组,GROUP BY col_name, ….,查询显示结果时,被分组的列如果有重复的值,只返回靠前的记录,并且 返回...
3.FIND_IN_SET(str,strlist) 如果字符串str在由N子串组成的表strlist之中,返回一个1到N的值。一个字符串表是被“,”分隔的子串组成的一个字符串。如果第一个参数是一个常数字符串并且第二个参数是一种类型为SET的列,FIND_IN_SET()函数被优化而使用位运算!如果str不是在strlist里面或如果 strlist是空字...
SET(val1, val2, val3, ...)A string object that can have 0 or more values, chosen from a list of possible values. You can list up to 64 values in a SET list Numeric Data Types Data typeDescription BIT(size)A bit-value type. The number of bits per value is specified insize. Th...
data2int, primarykey(name,data2) )shardkey=name; 创建一级 Range|List 分区表: 使用场景: 一级分区除了根据 shardkey 进行一致性 hash 分区,也可以根据实际场景进行 Range 或 List 进行一级分区。 Range 分区是指根据一定字段取值范围进行分区指定,适合例如日志流水表,可以根据一定日期范围进行分区,方便后续数...
A set. A string object that can have zero or more values, each of which must be chosen from the list of values 'value1', 'value2', ... SET values are represented internally as integers. A SET column can have a maximum of 64 distinct members. ...
执行结果(CALL list_emp(); -- 调用存储过程): --有参数的存储过程: DELIMITER $$ CREATE PROCEDURE count_emp(OUT total_emp INT) COMMENT '统计员工数量' BEGIN SELECT COUNT(*) INTO total_emp FROM tb_emp; END $$ DELIMITER ; SET @total_emp = 10; -- 声明变量 ...
Columns分区是在mysql5.5引进的分区类型,上面的分区是都是基于整形分区,是为了解决之前版本要进行函数或者表达式转换成整形,他分为 list columns 和 range columns ,他们支持 整形 日期 ,字符串, 整形:tinyint smallint ,mediumint ,int ,bigint ,其他类型不支持 ...
IntegrationRuntimeDataProxyProperties IntegrationRuntimeDebugResource IntegrationRuntimeEdition IntegrationRuntimeEntityReferenceType IntegrationRuntimeInternalChannelEncryptionMode IntegrationRuntimeLicenseType IntegrationRuntimeListResponse IntegrationRuntimeMonitoringData IntegrationRuntimeNodeIpAddress IntegrationRuntimeNodeMoni...
IntegrationRuntimeDataProxyProperties IntegrationRuntimeDebugResource IntegrationRuntimeEdition IntegrationRuntimeEntityReferenceType IntegrationRuntimeInternalChannelEncryptionMode IntegrationRuntimeLicenseType IntegrationRuntimeListResponse IntegrationRuntimeMonitoringData IntegrationRuntimeNodeIpAddress IntegrationRuntimeNodeMoni...
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