selectordinal_positionasColorder,column_nameasColumnName,data_typeasTypeName,coalesce(character_maximum_length,numeric_precision,-1)asLength,numeric_scaleasScale,caseis_nullablewhen'NO'then0else1endasCanNull,column_defaultasDefaultVal,casewhenposition('nextval'incolumn_default)>0then1else0endasIsIdentity,...
DECLARE v_id integer; v_name varchar(20); v_v1 constant number := 90; cursor c_cursor is select * from tablename where id = 0; BEGIN open c_cursor; /* 打开游标 */ loop fetch c_cursor into v_id, v_name; /* 从游标获取数据 */ exit when c_cursor%notfound; end loop; close ...
Maximum length of identifiers: 64 Maximum columns in an index: 32 Maximum size of a TOAST chunk: 1996 Size of a large-objectchunk: 2048 Date/time type storage: 64-bit integers Float4 argument passing: by value Float8 argument passing: by value Data page checksum version: 0 Mock authenticat...
test=# CREATE TABLE student(id SERIAL PRIMARY KEY, name VARCHAR, age INT NOT NULL); CREATE TABLE 2. 表文件的内部布局 前面创建了名为student的数据表,到此为止,还没有向该表中插入(INSERT INTO)过数据。因此student表的总行数是0。 test=# SELECT COUNT(*) FROM student; count --- 0 (1 row) ...
select col.table_schema, col.table_name, col.ordinal_position, col.column_name, col.data_type, col.character_maximum_length, col.numeric_precision, col.numeric_scale, col.is_nullable, col.column_default, des.description from information_schema.columns col left join pg_description des on col....
select * from information_schema.columns where table_name='表名' postgresql 查询所有数据库 SELECT * FROM pg_database; 查询表字段信息 test是表名 ,根据自己的来 select col.table_schema, col.table_name, col.ordinal_position, col.column_name, col.data_type, col.character_maximum_length, col...
SELECT column_name, data_type, character_maximum_length, is_nullable FROM information_schema.columns WHERE table_name = 'your_table_name'; 在上述查询语句中,将"your_table_name"替换为你要查询的表的名称。 该查询语句将返回表的每个列的名称、数据类型、字符最大长度和是否可为空的信息。 如果你还想...
offMaximum data alignment: 8Database block size: 8192Blocks per segment of large relation: 131072WAL block size: 8192Bytes per WAL segment: 16777216Maximum length of identifiers: 64Maximum columns in an index: 32Maximum size of a TOAST chunk: 1996Size of a large-object chunk: 2048Date/time ...
下表列出 Microsoft.DBforPostgreSQL/servers 資源類型的可用計量。 表格標題 計量- Azure 入口網站 中顯示的計量顯示名稱。 Rest API 中的名稱-REST API中所指的計量名稱。 單位- 量值單位。 匯總- 預設匯總類型。 有效值:Average、Minimum、Maximum、Total、Count。
-- Function: -- Generate a random string array -- Parameters: -- str_length: Length of string -- max_length: Maximum length of the array -- fixed_length: Whether the length of array is fixed. If it is true, the length of array will match max_length. create or replace function gen...