PostgreSQL 14.10 Documentation11 The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you'd need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won't fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 3032 页 | 13.27 MB | 1 年前3- PostgreSQL 14.10 Documentationshown above if you do: SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you'd need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won't fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2871 页 | 13.38 MB | 1 年前3
- PostgreSQL 9.6.24 DocumentationChapter 2. The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you’d need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won’t fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2814 页 | 6.58 MB | 1 年前3
- PostgreSQL 17beta1 US Documentation11 The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you'd need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won't fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 3188 页 | 14.32 MB | 1 年前3
- PostgreSQL 9.6.24 Documentation
SELECT * FROM weather ORDER BY city, temp_lo; 8 Chapter 2. The SQL Language You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you’d need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won’t fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2661 页 | 6.53 MB | 1 年前3
- PostgreSQL 17beta1 A4 Documentationshown above if you do: SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you'd need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won't fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 3017 页 | 14.45 MB | 1 年前3
- PostgreSQL 9.5 DocumentationChapter 2. The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you’d need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won’t fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2714 页 | 6.33 MB | 1 年前3
- PostgreSQL 8.4 Documentation......................................................1774 E.23.3.9.2. libpq SSL (Secure Sockets Layer) support .........................1774 E.23.3.9.3. ecpg ......................................... Chapter 2. The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you’d need to qualify the column names to show which one you meant0 码力 | 2371 页 | 5.09 MB | 1 年前3
- PostgreSQL 9.5.25 Documentation
SELECT * FROM weather ORDER BY city, temp_lo; 8 Chapter 2. The SQL Language You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you’d need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won’t fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2558 页 | 6.27 MB | 1 年前3
- PostgreSQL 13.14 Documentation11 The SQL Language SELECT * FROM weather ORDER BY city, temp_lo; You can request that duplicate rows be removed from the result of a query: SELECT DISTINCT city FROM weather; city --------------- all had different names, the parser automatically found which table they belong to. If there were duplicate column names in the two tables you'd need to qualify the column names to show which one you meant considered good style to qualify all column names in a join query, so that the query won't fail if a duplicate column name is later added to one of the tables. Join queries of the kind seen thus far can also0 码力 | 2940 页 | 12.89 MB | 1 年前3
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