PostgreSQL provides a built-in function named UNNEST() that expands the given array into rows. The UNNEST() function takes an array as an argument/parameter and expands the given array into a set of rows. In si
() function to expand an array created by the string_to_array() functionSELECTunnest(-- Expands the array into individual rowsstring_to_array(-- Converts a comma-separated string into an array'water,land,air',-- The comma-separated string to be converted','-- The delimiter used to ...
SELECT foo FROM regexp_split_to_table('the quick brown fox jumped over the lazy dog', E'\\s+') AS foo; foo --- the quick brown fox jumped over the lazy dog (9 rows) SELECT regexp_split_to_array('the quick brown fox jumped over the lazy dog', E'\\s+'); regexp_split_to...
函数:convert_from(string bytea, src_encoding name) 说明:Convertstringtothedatabaseencoding. The original encodingisspecifiedbysrc_encoding. The string must be validinthis encoding. 转换字符串编码,自己要指定源编码,目标编码默认为数据库指定编码, 例子:convert_from('text_in_utf8','UTF8')=text_in_...
PostgreSQL, is an open-source RDBMS that allows you to store or manage data in structured formats, using rows and columns. It also allows for semi-structured data management like JSON files and XML documents. One can query JSON data with Postgres, pull out individual values from it, and eve...
typarray:指向同类型的数组类型的Oid。typinput,typoutput:类型的输入输出函数,数据库进行对数字进行存储或者输出,首先由客户端获取数据 (一般为字符串 )进行转化,变为数据库能够使用的数据类型。输出函数亦然。typreceive,typsend:输入、输出转换函数,多用于二进制格式。typmodin,typmodout:对于变长的数据的输入、...
In PostgreSQL, the user can convert the data stored in JSON objects (as key-value pairs) to a set of table rows. This operation can be performed by making use of thejson_to_recordset()function. Thejson_to_recordset()function takes a JSON array, which can contain one or more JSON objec...
lazydog(9rows)SELECTregexp_split_to_array('the quick brown fox jumps over the lazy dog', E'\\s+'); regexp_split_to_array --- {the,quick,brown,fox,jumps,over,the,lazy,dog} (1row) SELECT foo FROMregexp_split_to_table('the quick brown fox...
/* array of input functions for each attrs */Oid*typioparams;/* array of element types for in_functions */int*defmap;/* array of default att numbers related to* missing att */ExprState**defexprs;/* array of default att expressions for all* att */bool*defaults;/* if DEFAULT marker...
convert(string using conversion_name) text 使用指定的转换名字改变编码。 convert('PostgreSQL' using iso_8859_1_to_utf8) 'PostgreSQL' lower(string) text 把字串转化为小写 lower('TOM') tom octet_length(string) int 字串中的字节数 octet_length('jose') 4 overlay(string placing string from int ...