ALTER TABLE table_name ALTER COLUMN column_name SET DATA TYPE new_data_type USING expression;其中...
ALTER [ COLUMN ] column TYPE type [ USING expression ] ALTER [ COLUMN ] column SET DEFAULT expression ALTER [ COLUMN ] column DROP DEFAULT ALTER [ COLUMN ] column { SET | DROP } NOT NULL ALTER [ COLUMN ] column SET STATISTICS integer ALTER [ COLUMN ] column SET STORAGE { PLAIN | EXT...
postgres=#altertabletb101alterid typeintusingid::int;ALTERTABLEpostgres=# \d tb101Table"public.tb101"Column|Type|Modifiers---+---+---id|integer| id::int 也可以使用cast(id as int)
(1row) postgres=#selectn_to_b(0); n_to_b---f (1row) postgres=#selectn_to_b(-1); n_to_b---t (1row) postgres=#altertabletblaltercolumnstat typebooleanusingstat::int::boolean;ALTERTABLEpostgres=#select*fromtbl limit10; id|stat---+---1|f2|f3|f4|f ... 字典化 postgres=#cr...
ERROR: column "id" cannot be cast automatically to type integer HINT: Specify a USING expression to perform the conversion.在没有隐式的转换下，就需要指定Using来显⽰的转换。5. 使⽤Using进⾏类型转换 postgres=# alter table tb101 alter id type int using id::int;ALTER TABLE postgres=#...
当列的类型为字符类型,当我们想修改为数值类型时,是无法成功的,这个时候我们可以通过以下方法进行修改。 如果表里有数据,谨慎使用!!!如果表里有数据,谨慎使用!!!如果表里有数据,谨慎使用!!! 代码语言:javascript 复制 ALTERTABLEthe_tableALTERCOLUMNcol_nameTYPEintegerUSING(col_name::integer); ...
ALTERTABLEpublic.table_nameADDcolumn col3 int; 八、pg删除字段 代码语言:javascript 复制 ALTERTABLEpublic.table_nameDROPCOLUMNifexists col3;ALTERTABLEpublic.table_nameDROPCOLUMNcol3 cascade; 九、pg修改字段类型 代码语言:javascript 复制 alter tablepublic.table_name alter column col1 type varcharUSINGcol...
ALTER COLUMN col_1 TYPE new_data_type, ALTER COLUMN col_2 TYPE new_data_type; Example: How to update data types of several columns using a single command in PostgreSQL? From the snippet shown in step 4 of the previous example, we can observe that the“team_rating”and“team_lead”colum...
To change the data type, or the size of a table column we have to use the ALTER TABLE statement.The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.The ALTER TABLE statement is also used to add and drop various constraints on an existing table....
PostgreSQL里有数组类型,那么 integer 和 integer[] 如何相互转换呢? integer[] -》 integer ALTER TABLE image ALTER COLUMN id TYPE INTEGER USING id[1]::INTEGER; 1. integer -》 integer[] ALTER TABLE image ALTER COLUMN id TYPE INTEGER [] ...