mysql>create tablef2(f1float(15,2));QueryOK,0rowsaffected(0.01sec)mysql>insert into f2values(123456789.39);QueryOK,1rowaffected(0.00sec)mysql>select*from f2;+---+|f1|+---+|123456792.00|+---+1rowinset(0.00sec) 最后你会发现,连整数都不准了,小数被完全抹去了。 第二个误区,对于存储而言,是...
mysql中的建表语句是【CREATE TABLE table_name (column_name column_type);】。column_name表示字段名,column_type表示字段类型。 语法: CREATE TABLE table_name (column_name column_type); 1. (推荐教程:mysql教程) 举例: 我们将在 RUN 数据库中创建数据表run_tbl:CREATE TABLE IF NOT EXISTS `run_tbl`...
mysql> INSERT INTO t VALUES(DEFAULT(i)); ERROR 1364 (HY000): Field 'i' doesn't have a default value mysql> select * from t; +---+ | i | +---+ | 0 | | 0 | +---+ 2 rows in set (0.01 sec) mysql> 对于给定的表,SHOW CREATE TABLE语句显示哪些列具有显式的DEFAULT子句。对于...
mysql>droptabletemp2; Query OK,0rowsaffected (0.15sec) mysql>createtabletemp2(idfloat(10,2),id2double(10,2),id3decimal(10,2)); Query OK,0rowsaffected (0.18sec) mysql>insertintotemp2values(1234567.21,1234567.21,1234567.21),(9876543.21,->9876543.12,9876543.12); Query OK,2rowsaffected (0.06sec...
mysql> create table temp2(id float(10,2),id2 double(10,2),id3 decimal(10,2)); Query OK, 0 rows affected (0.18 sec) mysql> insert into temp2 values(1234567.21, 1234567.21,1234567.21),(9876543.21, -> 9876543.12, 9876543.12); Query OK, 2 rows affected (0.06 sec) ...
mysql>create table f2(f1float(15,2)); QueryOK,0rows affected(0.01sec) mysql>insertintof2 values(123456789.39); QueryOK,1row affected(0.00sec) mysql>select*fromf2; +---+ |f1| +---+ |123456792.00| +---+ 1rowinset(0.00sec) 最后...
mysql>create table f2(f1float(15,2)); QueryOK,0rows affected(0.01sec) mysql>insertintof2 values(123456789.39); QueryOK,1row affected(0.00sec) mysql>select*fromf2; +---+ |f1| +---+ |123456792.00| +---+ 1rowinset(0.00sec) 最后...
以下是一个示例代码,展示如何在MySQL中比较两个DOUBLE类型的值: 代码语言:txt 复制 -- 创建一个示例表 CREATE TABLE example ( id INT PRIMARY KEY, value DOUBLE ); -- 插入一些示例数据 INSERT INTO example (id, value) VALUES (1, 0.1 + 0.2); INSERT INTO example (id, value) VALUES (2, 0.3)...
---+| 0 || -1.1000000000000005 |+---+2 rows in set (0.00 sec)mysql> alter table temp2 modify id decimal(10,5);Query OK, 2 rows affected (0.28 sec)Records: 2 Duplicates: 0 Warnings: 0mysql> alter table temp2 modify id2 decimal(10,5);Query OK, 2 rows affected (0.15 s...
double类型不只是在MySQL中存在精度错误的问题,在oracle、Java等平台同样存在此问题,如下: 简单的0.2+0.4,但是返回的结果不是0.6。 回到问题开始 如果换成DECIMAL类型,round的结果将是正确的,如下: yujx>drop table dd; yujx>create table dd (a double,b decimal(30,10)); ...