-- SCHEMA: schema2023-- DROP SCHEMA schema2023 ;CREATESCHEMA schema2023AUTHORIZATIONpostgres;-- Table: schema2023.some_info-- DROP TABLE schema2023.some_info;CREATETABLEIFNOTEXISTSschema2023.some_info ( idcharactervarying(128)COLLATEpg_catalog."default"NOTNULL, namecharactervarying(100)COLLATEpg_cata...
--Create Users tableCREATE TABLE IF NOT EXISTS users( id bigserial NOT NULL, name character varying(100) NOT NULL,rating integer,PRIMARY KEY (id));CREATE INDEX usr_rating_idxON users USING btree(rating ASC NULLS LAST)TABLESPACE pg_default;--Create Stories tableCREATE TABLE IF NOT EXISTS...
\d<table_name>\d+<table_name>SELECTcolumn_name,data_type,character_maximum_lengthFROMINFORMATION_SCHEMA.COLUMNSWHEREtable_name='<table_name>'; 创建表 CREATETABLE<table_name>(<column_name><column_type>,<column_name><column_type>); 创建表,主键自增 ...
mydb=# \dt gxl.*Did not find any relation named"gxl.*"# 如果模式中没有表就会返回这个提示# 创建表mydb=# create table gxl.test2(id int,name varchar(32), age int);CREATE TABLE# 查看表mydb=# \dt gxl.*List of relations Schema | Name | Type | Owner ---+---+---+--- gxl | ...
CREATE TABLE IF NOT EXISTS users ( id bigserial NOT NULL, name character varying(100) NOT NULL, rating integer, PRIMARY KEY (id) ) ; CREATE INDEX usr_rating_idx ON users USING btree (rating ASC NULLS LAST) TABLESPACE pg_default
\d <table_name> \d+ <table_name> SELECT column_name, data_type, character_maximum_length FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = '<table_name>'; 创建表 CREATE TABLE <table_name>( <column_name> <column_type>, <column_name> <column_type> ); 创建表,主键自增 CREATE TABLE...
name character varying(100) NOT NULL, rating integer, PRIMARY KEY (id) ) ; CREATE INDEX usr_rating_idx ON users USING btree (rating ASC NULLS LAST) TABLESPACE pg_default ; --Create Stories table CREATE TABLE IF NOT EXISTS stories
create table tb4( id BIGSERIAL not null primary key,-- 不允许为空,&主键&自增 name varchar(16) not null, --允许为空 email varchar(32) null, -- 可以为空(默认) age int default 3 -- 插入数据,不给值,默认值为3 ); 1. 2.
\d <table_name> \d+ <table_name> SELECT column_name, data_type, character_maximum_length FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = '<table_name>'; 创建表 CREATE TABLE <table_name>( <column_name> <column_type>, <column_name> <column_type> ); 创建表,主键自增 CREATE TABLE...
使用limit 1的语法如下: SELECT * FROM table_name LIMIT 1; 这条语句将返回表table_name中的第一行记录。 在Postgres中使用limit 1的优势是可以提高查询效率,特别是当查询结果集很大时。通过限制返回的行数,可以减少数据传输和处理的开销,提升查询性能。