numeric, int, 和 bigint 类型可以转为 money. 从 real 和 double precision 则需要先转为 numeric first, 例如 SELECT'12.34'::float8::numeric::money; money 可以无损转换为 numeric, 转换为其他类型则会有精度损失, 例如 SELECT'52093.89'::money::numeric::float8; 字符串类型 二进制类型 二进制表示, ...
null values are used. The result set contains all matching rows as well as any non-matching rows, with columns populated from both joined tables. This type of join is useful for selecting data from multiple tables in a single
The Inner Join is used to determine which rows of the tables that participated in JOIN needs to be considered to return after verifying the condition. Also, we can use the ON or USING clause to join the condition. ON clause It matches the common columns of the tables participating in JOIN...
Creating a multicolumn index in PostgreSQL is a common practice when we want to create an index on multiple columns. 在PostgreSQL 中创建多列索引是一种常见的做法,因为我们要在多列上创建索引。 PostgreSQL Index Types The PostgreSQL index facilitates the efficient retrieval of data from the table. Th...
Here is the generic syntax for the INNER JOIN clause that joins two tables: SELECT select_list FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name; In this syntax: First, specify the columns from both tables in the select list of the SELECT clause. Second, specify...
Desired output: Unnesting the arrays produces the correct result: SELECTp_keyasf_key,unnest(array['a','b','c']) col,unnest(array[col_a, col_b, col_c]) valFROMtbl_wide However, given the number of columns and tables to convert I would like to use a reference table: ...
Prevent unnecessary checkpoints and WAL archiving on otherwise-idle systems (Michael Paquier) Increase the maximum configurable WAL segment size to one gigabyte (Beena Emerson) Add columns to pg_stat_replication to report replication delay times (Thomas Munro) The new columns are write_lag, flus...
I don't think that there is any fundamental reason that it could not be changed to allow it to use hashing, it just hasn't been done yet. It is complicated by the fact that you can have multiple count() expressions in the same query which demand sorting/grouping on different columns....
Support unique constraints on nullable columns. Escape hatch babelfishpg_tsql.escape_hatch_unique_constraint has been deprecated. Introduced support to correlated subquery transform and cache for enhancement of query performance by transforming scalar correlated subquery into join query, or caching the sub...
postgresql 查找PL/PGSQL函数以返回N列如果不在某个地方对列列表进行硬编码（无论是在调用函数时还是在...