安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
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- what does the @ gt; operator in postgres do? - Stack Overflow
The at sign (@) is optional noise The amounts of the different units are implicitly added with appropriate sign accounting ago negates all the fields This syntax is also used for interval output, if IntervalStyle is set to postgres_verbose
- syntax - What does :: do in PostgreSQL? - Stack Overflow
A type cast specifies a conversion from one data type to another PostgreSQL accepts two equivalent syntaxes for type casts, the PostgreSQL-specific value::type and the SQL-standard CAST(value AS type)
- Meaning of different command line prompts in PostgreSQL?
psql (9 1 10) Type "help" for help postgres=# CREATE DATABASE exampledb postgres-# After I entered the CREATE DB command the prompt changed from ending with "=#" to "-#" I would like to know what this change means and what the implications are for receiving and processing commands
- What is the difference between `- gt; gt;` and `- gt;` in Postgres SQL?
Postgres offers 2 operators to get a JSON member: the arrow operator: -> returns type JSON or JSONB; the double arrow operator: ->> returns type text; We must also understand that we now have 2 different kinds of null: (null) postgres null type; null json b null type; I created an example on jsfiddle Let's create a simple table with a JSONB field:
- sql - PostgreSQL IF statement - Stack Overflow
How can I do such query in Postgres? IF (select count(*) from orders) gt; 0 THEN DELETE from orders ELSE INSERT INTO orders values (1,2,3);
- database - PostgreSQL DESCRIBE TABLE - Stack Overflow
In postgres \d is used to describe the table structure e g \d schema_name table_name this command will provide you the basic info of table such as, columns, type and modifiers If you want more info about table use \d+ schema_name table_name this will give you extra info such as, storage, stats target and description
- Postgresql SELECT if string contains - Stack Overflow
One thing non-intuitive thing is that for postgres, position is 1 based, not 0 based For example select position('a' in 'abc') returns 1 And if there is no match it returns 0
- sql - Not equal and null in Postgres - Stack Overflow
In PostgreSQL: <> or != means Not equal, but cannot treat NULL as a comparable value IS DISTINCT FROM means Not equal, and can treat NULL as a comparable value
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