PostgreSQL用psql导入sql文件
2022/8/31 2:22:48
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一、sql文件
--------------------------------------------------------------------------- -- -- basics.sql- -- Tutorial on the basics (table creation and data manipulation) -- -- -- src/tutorial/basics.source -- --------------------------------------------------------------------------- ----------------------------- -- Creating a New Table: -- A CREATE TABLE is used to create base tables. PostgreSQL has -- its own set of built-in types. (Note that SQL is case- -- insensitive.) ----------------------------- CREATE TABLE weather ( city varchar(80), temp_lo int, -- low temperature temp_hi int, -- high temperature prcp real, -- precipitation date date ); CREATE TABLE cities ( name varchar(80), location point ); ----------------------------- -- Populating a Table With Rows: -- An INSERT statement is used to insert a new row into a table. There -- are several ways you can specify what columns the data should go to. ----------------------------- -- 1. The simplest case is when the list of value correspond to the order of -- the columns specified in CREATE TABLE. INSERT INTO weather VALUES ('San Francisco', 46, 50, 0.25, '1994-11-27'); INSERT INTO cities VALUES ('San Francisco', '(-194.0, 53.0)'); -- 2. You can also specify what column the values correspond to. (The columns -- can be specified in any order. You may also omit any number of columns, -- e.g., unknown precipitation below. INSERT INTO weather (city, temp_lo, temp_hi, prcp, date) VALUES ('San Francisco', 43, 57, 0.0, '1994-11-29'); INSERT INTO weather (date, city, temp_hi, temp_lo) VALUES ('1994-11-29', 'Hayward', 54, 37); ----------------------------- -- Querying a Table: -- A SELECT statement is used for retrieving data. The basic syntax is -- SELECT columns FROM tables WHERE predicates. ----------------------------- -- A simple one would be: SELECT * FROM weather; -- You may also specify expressions in the target list. (The 'AS column' -- specifies the column name of the result. It is optional.) SELECT city, (temp_hi+temp_lo)/2 AS temp_avg, date FROM weather; -- If you want to retrieve rows that satisfy certain condition (i.e., a -- restriction), specify the condition in WHERE. The following retrieves -- the weather of San Francisco on rainy days. SELECT * FROM weather WHERE city = 'San Francisco' AND prcp > 0.0; -- Here is a more complicated one. Duplicates are removed when DISTINCT is -- specified. ORDER BY specifies the column to sort on. (Just to make sure the -- following won't confuse you, DISTINCT and ORDER BY can be used separately.) SELECT DISTINCT city FROM weather ORDER BY city; ----------------------------- -- Joins Between Tables: -- queries can access multiple tables at once or access the same table -- in such a way that multiple instances of the table are being processed -- at the same time. ----------------------------- -- The following joins the weather table and the cities table. SELECT * FROM weather JOIN cities ON city = name; -- This prevents a duplicate city name column: SELECT city, temp_lo, temp_hi, prcp, date, location FROM weather JOIN cities ON city = name; -- since the column names are all different, we don't have to specify the -- table name. If you want to be clear, you can do the following. They give -- identical results, of course. SELECT weather.city, weather.temp_lo, weather.temp_hi, weather.prcp, weather.date, cities.location FROM weather JOIN cities ON weather.city = cities.name; -- Old join syntax SELECT * FROM weather, cities WHERE city = name; -- Outer join SELECT * FROM weather LEFT OUTER JOIN cities ON weather.city = cities.name; -- Suppose we want to find all the records that are in the temperature range -- of other records. w1 and w2 are aliases for weather. SELECT w1.city, w1.temp_lo, w1.temp_hi, w2.city, w2.temp_lo, w2.temp_hi FROM weather w1 JOIN weather w2 ON w1.temp_lo < w2.temp_lo AND w1.temp_hi > w2.temp_hi; ----------------------------- -- Aggregate Functions ----------------------------- SELECT max(temp_lo) FROM weather; SELECT city FROM weather WHERE temp_lo = (SELECT max(temp_lo) FROM weather); -- Aggregate with GROUP BY SELECT city, max(temp_lo) FROM weather GROUP BY city; -- ... and HAVING SELECT city, max(temp_lo) FROM weather GROUP BY city HAVING max(temp_lo) < 40; ----------------------------- -- Updates: -- An UPDATE statement is used for updating data. ----------------------------- -- Suppose you discover the temperature readings are all off by 2 degrees as -- of Nov 28, you may update the data as follow: UPDATE weather SET temp_hi = temp_hi - 2, temp_lo = temp_lo - 2 WHERE date > '1994-11-28'; SELECT * FROM weather; ----------------------------- -- Deletions: -- A DELETE statement is used for deleting rows from a table. ----------------------------- -- Suppose you are no longer interested in the weather of Hayward, then you can -- do the following to delete those rows from the table. DELETE FROM weather WHERE city = 'Hayward'; SELECT * FROM weather; -- You can also delete all the rows in a table by doing the following. (This -- is different from DROP TABLE which removes the table in addition to the -- removing the rows.) DELETE FROM weather; SELECT * FROM weather; ----------------------------- -- Removing the tables: -- DROP TABLE is used to remove tables. After you have done this, you -- can no longer use those tables. ----------------------------- DROP TABLE weather, cities;
在psql里面执行 \i basics.sql
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