shulanxtdb=#CREATETRIGGERexample_trigger AFTERINSERTONCOMPANYFOREACH ROWEXECUTEPROCEDUREauditlogfunc(); auditlogfunc() 是 PostgreSQL 一个程序,其定义如下: CREATEORREPLACEFUNCTIONauditlogfunc()RETURNSTRIGGERAS$example_table$BEGININSERTINTOAUDIT(EMP_ID, ENTRY_DATE)VALUES(new.ID,current_timestamp);RETURNNEW...
等同于create database 语法,创建一个数据库,支持远程执行 3.createuser createuser creates a new PostgreSQL role. createuser [OPTION]... [ROLENAME] -c, --connection-limit=N connection limit for role (default: no limit) -d, --createdb role can create new databases -D, --no-createdb role ...
We’ll show you how to create other index types. PostgreSQL CREATE INDEX statement example We’ll use the address table from the sample database for the demonstration: First, connect to the PostgreSQL dvdrental sample database using psql: psql -U postgres -d dvdrental Second, execute the ...
WITH english_stem; CREATE INDEX idx_article_text ON articles USING gin(to_tsvector('english_custom', content)); 3. 使用PL/pgSQL优化查询 3.1 编写基本的查询函数 CREATE OR REPLACE FUNCTION search_articles(search_query TEXT) RETURNS TABLE(id INT, title TEXT, content TEXT) AS $$ BEGIN RETURN ...
-- numeric booster example + log(NumberOfVotes)*0.01 FROM movies WHERE search @@ websearch_to_tsquery('english','jedi') ORDER BY rank DESC LIMIT 10; 1. 2. 3. 4. 5. 6. 7. 对数函数用于平滑影响,而0.01因子使得提升与排名得分具有可比性。
SELECT title, ts_rank(search, websearch_to_tsquery('english', 'jedi')) -- numeric booster example + log(NumberOfVotes)*0.01 FROM movies WHERE search @@ websearch_to_tsquery('english','jedi') ORDER BY rank DESC LIMIT 10; 对数函数用于平滑影响,而0.01因子使得提升与排名得分具有可比性。
c:\>psql exampledb < user.sql // 将user.sql文件导入到exampled数据库中 postgres=# \h select // 精细显示SQL命令中的select命令的使用方法 postgres=# \l // 显示所有数据库 postgres=# \dt // 显示当前数据库中的所有表 postgres=# \d [table_name] // 显示当前数据库的指定表的表结构 ...
FunctionDescriptionExampleExample Result num_nonnulls(VARIADIC "any") returns the number of non-null arguments num_nonnulls(1, NULL, 2) 2 num_nulls(VARIADIC "any") returns the number of null arguments num_nulls(1, NULL, 2) 1 算数 运算符 函数 随机值函数 三角函数 字符串 常用字符串操作符...
Several of the Boolean flags in pg_class are maintained lazily: they are guaranteed to be true if that's the correct state, but may not be reset to false immediately when the condition is no longer true. For example, relhasindex is set by CREATE INDEX, but it is never cleared by DROP...
CREATE INDEX btree_idx on test_idx USING BTREE (id); \d+ test_idx; Output: image.png Explanation:In the above example, we have created an index on the id column in the test_idx table. We have also defined the name as btree_idx to the newly created index. ...