例:select prd_no,sum(qty)from sales group by prd_no6.COUNT_BIG返回指定组中的项目数量,与COUNT函数不同的是COUNT_BIG返回bigint值,而COUNT返回的是int值。 例:selectcount_big(prd_no)from sales7.GROUPING产生一个附加的列,当用CUBE或ROLLUP运算符添加
Size data_size, uint16 *infomask, bits8 *bit) { bits8 *bitP; int bitmask; int i; int numberOfAttributes = tupleDesc->natts; #ifdef USE_ASSERT_CHECKING char *start = data; #endif if (bit != NULL) { bitP = &bit[-1]; bitmask = HIGHBIT; } else { /* just to keep compiler ...
postgres 字符串 截取 本节描述了用于检查和操作字符串数值的函数和操作符。在这个环境中的字符串包括所有 character, character varying, text 类型的值。除非另外说明,所有下面列出的函数都可以处理这些类型,不过要小心的是,在使用 character SQL 定义了一些字符串函数,它们有指定的语法(用特定的关键字而不是逗号来...
函数:convert(string bytea, src_encoding name, dest_encoding name) 说明:Convert string to dest_encoding. The original encoding is specified by src_encoding. The string must be valid in this encoding. Conversions can be defined by CREATE CONVERSION. Also there are some predefined conversions. See...
bigint number bigserial, serial8 number bit string Fixed-length bit string (e.g. "0100"). bit varying, varbit string Variable-length bit string (e.g. "0100"). boolean, bool boolean box string bytea string Variable length binary string with hex output format prefixed with "\x" ...
char_length(string) int 字串中的字符个数 char_length('jose') 4 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(strin...
JSON() - Converts a given expression specified as text or bytea string (in UTF8 encoding) into a JSON value JSON('{"a":123, "b":[true,"foo"], "a":"bar"}'){"a":123, "b":[true,"foo"], "a":"bar"} JSON_SCALAR() - Converts a given SQL scalar value into a JSON sc...
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NUMBER(n, m) NUMERIC(n,m) NUMERIC(n,m)NUMBER(n, m) NUMBER type can be converted to NUMERIC, which is unlimited in size. However, the SMALLINT, INT BIGINT, REAL, and DOUBLE PRECISION data types offer better performance. NUMBER(4) SMALLINT NUMBER(4)SMALLINT NUMBER(...
bdr.show_workers(worker_pidint,worker_roleint,worker_role_nametext,worker_subid oid) bdr.show_writers Function used in thebdr.writersview. bdr.sync_status_name Converts sync state code into a textual representation. Used mainly to implement thebdr.sync_node_requests_summaryview. ...