前言
DB2与MySQL语法比较相似
基本操作
连接数据库
# 连接到schema
db2 connect to <schemaName>
# 切换schema
db2 set current schema <schemaName>
查看表结构
describe table <tableName>
增
insert into table_name(column_name, ...)
values(theValue, ...)
删
delete from table_name where column_name = theValue
查
select column_name from table_name
where column_name = theValue
union重复记录不显示
改
update table_name
set column_name = newValue
...
常用函数
CHAR()、INR()、
强制类型转换 CAST (expression AS data_type)
CAST(theValue AS char(10))
截取字符串 substr(字符串,截取开始位置,截取长度)
脚本
执行sql脚本
db2 -td@ -vf <sqlFileName>
新增字段
BEGIN
IF NOT EXISTS (
SELECT colname FROM SYSCAT.COLUMNS
WHERE TABNAME = '' AND COLNAME = '' AND TABSCHEMA = ''
)
THEN
EXECUTE IMMEDIATE
'ALTER <TABLE tableName> ADD <columnName> VARCHAR(10)'
