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Kingbasees SQL language reference manual of Jincang database (8. Function (V))

2022-07-23 10:27:00 【Thousands of sails passed by the side of the sunken boat_】

8.140. HAS_ANY_COLUMN_PRIVILEGE

usage ：
has_any_column_privilege(user, table, privilege)
has_any_column_privilege(table, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether any column of a table can be accessed in a specific way . The desired access type must be a combination of the following values ：SELECT、INSERT、UPDATE or REFERENCES. Note that having any of these permissions at the table level will implicitly grant it to each column on the table .
Example ：
CREATE TABLE tbl();
SELECT  has_any_column_privilege('tbl', 'INSERT, UPDATE, REFERENCES');

8.141. HAS_COLUMN_PRIVILEGE

usage ：
has_column_privilege(user, table, column, privilege)
has_column_privilege(table,column, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a table can be accessed in a specific way column Specified column . has_column_privilege Check whether a user can access a column in a specific way . Its parameter possibility is similar to has_table_privilege similar , And the column can also be specified by name or attribute number . The desired access type must be a combination of the following values ：SELECT、INSERT、UPDATE or REFERENCES. Note that having any of these permissions at the table level will implicitly grant it to each column on the table .
Example ：
SELECT has_column_privilege(9999,'nosuchcol','select');
SELECT has_column_privilege('mytable','f2','select');

8.142. HAS_DATABASE_PRIVILEGE

usage ：
has_database_privilege(user, database, privilege)
has_database_privilege(database, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether it is possible to privilege Specify how to access database database . The desired access type must be some combination of the following values ：CREATE、CONNECT、TEMPORARY or TEMP（ Equivalent to TEMPORARY）.
Example ：
SELECT  has_database_privilege(current_database(), 'CONNECT');

8.143. HAS_FOREIGN_DATA_WRAPPER_PRIVILEGE

usage ：
has_foreign_data_wrapper_privilege(user, fdw, privilege)
has_foreign_data_wrapper_privilege(fdw, privilege)
function ：
Check ``user`` user （ If not specified, use the current user ） Whether an external data wrapper can be accessed in a specific way . Its parameter possibility is similar to has_table_privilege. The desired access type must be USAGE.
Example ：
SELECT has_foreign_data_wrapper_privilege('foo', 'USAGE');

8.144. HAS_FUNCTION_PRIVILEGE

usage ：
has_function_privilege(user, function, privilege)
has_function_privilege(function, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a function can be accessed in a specific way . The parameter possibility is similar has_table_privilege. Using a text string instead of OID When specifying a function , Allowed inputs and regprocedure The data types are the same （ Refer to the Object identifier type ）. The desired access type must be EXECUTE.
Example ：
SELECT has_function_privilege('joeuser', 'myfunc(int, text)', 'execute');

8.145. HAS_LANGUAGE_PRIVILEGE

usage ：
has_language_privilege(user, language, privilege)
has_language_privilege(language, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a process language can be accessed in a specific way . The desired access type must be USAGE.
Example ：
SELECT  has_database_privilege(current_database(), 'CONNECT');

8.146. HAS_SCHEMA_PRIVILEGE

usage ：
has_schema_privilege(user, schema, privilege)
has_schema_privilege(schema, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether it is possible to privilege Specify how to access schema . The desired access type must be CREATE or USAGE.
Example ：
SELECT has_schema_privilege('public', 'USAGE');

8.147. HAS_SEQUENCE_PRIVILEGE

usage ：
has_sequence_privilege(user, sequence, privilege)
has_sequence_privilege(sequence, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a sequence can be accessed in a particular way . The type of access you want to test must be one of the following ：USAGE、SELECT or UPDATE.
Example ：
CREATE SEQUENCE x_seq;
SELECT has_sequence_privilege('x_seq', 'SELECT');

8.148. HAS_SERVER_PRIVILEGE

usage ：
has_server_privilege(user, server, privilege)
has_server_privilege(server, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether you can access an external server in a specific way . The desired access type must be CREATE or USAGE.
Example ：
SELECT has_server_privilege('regress_test_role',(SELECT oid FROM pg_foreign_server WHERE srvname='s8'), 'USAGE');

8.149. HAS_TABLE_PRIVILEGE

usage ：
has_table_privilege(user, table, privilege)
has_table_privilege(table,privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a table can be accessed in a specific way . The user can use the name or OID （sys_authid.oid） To specify the , It can also be used. public Express PUBLIC Pseudo role . If this parameter is omitted , Then use current_user. The table can be by name or OID Appoint （ therefore , There are actually six kinds of has_table_privilege A variation of the , We can distinguish them by the number and type of their parameters ） . If specified by name , Then the name can be schema qualified if necessary . The desired permission type is specified with a text string , It must be one of the following values ： SELECT、INSERT、UPDATE、DELETE、TRUNCATE、REFERENCES or TRIGGER.WITH GRANT OPTION You can choose to add to a permission type to test whether the permission is obtained by using the delegation option . in addition , You can use commas to separate multiple permission types , In this case, as long as you have one of the permissions, the result is really （ The case of the permission string is not important , Additional white space can appear between permission names , However, there must be no blank space inside the permission name ）.
Example ：
SELECT has_table_privilege('myschema.mytable', 'select');
SELECT has_table_privilege('joe', 'mytable', 'INSERT, SELECT WITH GRANT OPTION');

8.150. HAS_TABLESPACE_PRIVILEGE

usage ：
has_tablespace_privilege(user, tablespace, privilege)
has_tablespace_privilege(tablespace, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a table space can be accessed in a specific way . The parameter possibility is similar ``has_table_privilege``. The desired access type must be CREATE.
Example ：
CREATE TABLESPACE mytsp LOCATION '/path/to/mytsp';
SELECT has_tablespace_privilege('mytsp', 'CREATE');

8.151. HAS_TYPE_PRIVILEGE

usage ：
has_type_privilege(user, type, privilege)
has_type_privilege(type, privilege)
function ：
Check user user （ If not specified, use the current user ） Whether a type can be accessed in a specific way . The possibility of its parameters is similar to has_table_privilege. Using strings instead of OID When specifying the type , Allowed inputs and regtype Same data type （ see Object identifier type ）. The expected access privilege type must be equal to USAGE.
Example ：
SELECT has_type_privilege('int8', 'USAGE');

8.152. HEIGHT

usage ：
height(box)
function ：
Geometric functions , Returns the vertical dimension of the box
Example ：
SELECT height(box '((0,0),(1,1))');

8.153. HOST

usage ：
height(inet)
function ：
inet function , extract IP Address is text .
Example ：
SELECT host('192.168.1.5/24');

8.154. HOSTMASK

usage ：
hostmask(inet)
function ：
inet function , Construct a host mask for the network address .
Example ：
SELECT hostmask('192.168.23.20/30');

8.155. IF

usage ：
if(expr1 INT Compatibility type , expr2  Any type , expr3  Any type )
function ：
If expr1 Not for NULL also expr1 It's not equal to 0, return expr2 As a result , Otherwise return to expr3.
Parameter description ：
expr1 yes INTEGER Type expressions can be converted into INTEGER The type of .
expr2 The data type can be one of the data types of the system ( Such as ：TEXT,INTEGER,FLOAT etc. ).
expr3 The data type can be one of the data types of the system ( Such as ：TEXT,INTEGER,FLOAT etc. ).
Return value description ：
The data type of the return value ： The return type depends on expr2,expr3 The type of .
Example ：
SELECT IF(100, 'T', 'F') AS RESULT1,
       IF(1 - 1, 'T', 'F') AS RESULT2,
       IF('100', 'T', 'F') AS RESULT3,
       IF(NULL, 'T', 'F') AS RESULT4;

8.156. IFNULL

usage ：
ifnull(expr1, expr2)
function ：
When ``expr1`` No NULL,IFNULL return ``expr1``. Otherwise it returns ``expr2``
Example ：
SELECT ifnull(NULL,'exp2');
SELECT ifnull('exp1','exp2');

8.157. INET_CLIENT_ADDR

usage ：
inet_client_addr()
function ：
inet_client_addr Returns the... Of the current client IP Address . If the connection is through Unix Domain socket , return NULL.
Example ：
SELECT inet_client_addr();

8.158. INET_CLIENT_PORT

usage ：
inet_client_port()
function ：
inet_client_port Return the port number of the current client . If the connection is through Unix Domain socket , return NULL.
Example ：
SELECT inet_client_port();

8.159. INET_MERGE

usage ：
inet_merge(inet,inet)
function ：
inet_merge Returns the smallest network including a given network .
Example ：
SELECT inet_merge('192.168.1.5/24', '192.168.2.5/24');

8.160. INET_SAME_FAMILY

usage ：
inet_same_family(inet, inet)
function ：
Judge whether the addresses are the same IP Protocol family .
Example ：
SELECT inet_same_family(('192.168.1.5/24', '::1'));

8.161. INET_SERVER_ADDR

usage ：
inet_server_addr()
function ：
inet_server_addr Returns the of the server that accepts the current connection IP. If the connection is through Unix Domain socket , return NULL.
Example ：
SELECT inet_server_addr();

8.162. INET_SERVER_PORT

usage ：
inet_server_port()
function ：
inet_server_port Returns the port number of the server that accepts the current connection . If the connection is through Unix Domain socket , return NULL.
Example ：
SELECT inet_server_port();

8.163. INITCAP

usage ：
initcap(string)
function ：
INITCAP return char, The first letter of each word is capitalized , All other letters are lowercase . Words are separated by spaces or non alphanumeric characters .
char It can be any data type CHAR、VARCHAR、NCHAR or NVARCHAR. Return value and The same data type char. The database sets the initial character case based on the binary mapping defined for the base character set .
Example ：
The following example capitalizes each word in a string ：
SELECT initcap('hi THOMAS');

8.164. INSERTCHILDXML

usage ：
insertchildxml(xml_instance xml, xpath text, child_expr text , value_expr xml)
insertchildxml(xml_instance xml, xpath text , child_expr text ,value_expr xml, namespace _text)
function ：
function insertchildxml take ``value_expr`` The value provided is used as ``xpath`` The child nodes of the specified node are inserted into ``xml_instance`` in . If successful, the inserted ``xml_instance`` data , Failure returns ERROR.
Before using this function, you need to create kdb_utils_function Expand .
Example ：
SELECT insertchildxml('<a>one three </a>', '//b', 'name', '<name>newnode</name>');
SELECT insertchildxml('<a xmlns="http://example.com">test</a>', '//mydefns:b/text()', 'name', '<name>newnode</name>', ARRAY[ARRAY['mydefns', 'http://example.com']]);

8.165. INSERTCHILDXMLAFTER

usage ：
insertchildxmlafter(xml_instance xml, xpath text, child_expr text , value_expr xml)
insertchildxmlafter(xml_instance xml, xpath text , child_expr text ,value_expr xml,namespace _text)
function ：
function insertchildxmlafter take ``value_expr`` One or more collection elements provided as ``xpath`` The child element of the specified target parent element is inserted into ``child_expr`` After the specified existing collection element . If successful, the inserted ``xml_instance`` data , Failure returns ERROR.
Before using this function, you need to create kdb_utils_function Expand .
Example ：
In all of the specified nodes “b” Insert after the child node ：
SELECT insertchildxmlafter('<a>onetwofour</a>', '/a', 'b', '<c>three</c>');
At the first of the specified nodes “b” Insert after the child node
SELECT insertchildxmlafter('<a>onetwofour</a>', '/a', 'b[1]', '<c>three</c>');
In the second of the specified node “b” Insert after the child node
SELECT insertchildxmlafter('<a>onetwofour</a>', '/a', 'b[2]', '<c>three</c>');

8.166. INSERTCHILDXMLBEFORE

usage ：
insertchildxmlbefore(xml_instance xml, xpath text, child_expr text , value_expr xml)
insertchildxmlbefore(xml_instance xml, xpath text , child_expr text , value_expr xml,namespace _text)
function ：
function insertchildxmlbefore take ``value_expr`` One or more collection elements provided as ``xpath`` The child element of the specified target parent element is inserted into ``child_expr`` Before the specified existing collection element . If successful, the inserted ``xml_instance`` data , Failure returns ERROR.
Before using this function, you need to create kdb_utils_function Expand .
Example ：
In all of the specified nodes “b” Insert before the child node ：
SELECT insertchildxmlbefore('<a>one23two<d>four</d></a>', '/a', 'b', '<c>three</c>');
At the first of the specified nodes “b” Insert before the child node ：
SELECT insertchildxmlbefore('<a>onetwo</a>', '/a', 'b[1]', '<c>three</c>');
In the second of the specified node “b” Insert before the child node ：
SELECT insertchildxmlbefore('<a>one23two<d>four</d></a>', '/a', 'b[2]', '<c>three</c>');

8.167. INSERTXMLAFTER

usage ：
insertxmlafter(xml_instance xml, xpath text , value_expr xml)
insertxmlafter(xml_instance xml, xpath text , value_expr xml,namespace _text)
function ：
function insertxmlafter take ``value_expr`` The value provided is inserted into ``xpath`` After the specified node . If successful, the inserted ``xml_instance`` data , Failure returns ERROR.
Before using this function, you need to create kdb_utils_function Expand .
Example ：
SELECT insertxmlafter('<a xmlns="http://example.com">test</a>', '//mydefns:b/text()', '<name>newnode</name>', ARRAY[ARRAY['mydefns', 'http://example.com']]);

8.168. INSERTXMLBEFORE

usage ：
insertxmlbefore(xml_instance xml, xpath text , value_expr xml)
insertxmlbefore(xml_instance xml, xpath text , value_expr xml,namespace _text)
function ：
function insertxmlbefore take ``value_expr`` The value provided is inserted into ``xpath`` Before the specified node . If successful, the inserted ``xml_instance`` data , Failure returns ERROR.
Before using this function, you need to create kdb_utils_function Expand .
Example ：
SELECT insertxmlbefore('<a>b</a>','/a/b','<c>c</c>');
SELECT insertxmlbefore('<a></a>','/a/b','<c>c</c>');
SELECT insertxmlbefore('<a></a>','/a/b','<c></c>');
SELECT insertxmlbefore('<a xmlns="http://example.com">test</a>', '//mydefns:b/text()', '<name>newnode</name>', ARRAY[ARRAY['mydefns', 'http://example.com']]);

8.169. INSTR

usage ：
instr(expr1 text, expr2 text,[expr3 int[,expr4 int]])
function ：
In the parent string expr1 No expr3 A place （ from 1 Start ） Start to find the number expr4 The position of the substring of the second occurrence ,0 Indicates that it does not contain a substring expr2. If expr3 Negative , From expr1 The last of expr3 Reverse lookup started at , The position is still calculated from the beginning of the string .
Example ：
SELECT instr('bcaaaaabbc', 'a', -2);

8.170. INSTRB

usage ：
instrb(expr1 text,expr2 text,[expr3 int[,expr4 int]])
function ：
In the parent string expr1 No expr3 A place （ from 1 Start ） Start to find the number expr4 The position of the substring of the second occurrence , 0 Indicates that it does not contain a substring expr2. If expr3 Negative , From expr1 The last of expr3 Reverse lookup started at , The position is still calculated from the beginning of the string .
Example ：
SELECT instrb(’bcaaaaabbc’, ’a’, -2);

8.171. ISEMPTY

usage ：
isempty(anyrange)
function ：
Range of judgment anyrange Is it empty .
Example ：
SELECT isempty(numrange(1.1,2.2));

8.172. ISFINITE

usage ：
isfinite(date)
isfinite(timestamp)
isfinite(interval)
function ：
Judge whether the incoming parameter is a finite value .
Example ：
SELECT isfinite(date '2001-02-16');
SELECT isfinite(timestamp '2001-02-16 21:28:30');
SELECT isfinite(interval '4 hours');

8.173. ISNULL

usage ：
isnull(expr1 Any type , expr2 Any type )
function ：
Equivalent to function NVL(expr1 Any type , expr2 Any type ). When expr1 by NULL when , use expr2 Replace the value of this expression ; Otherwise, the value of this function remains expr1 Original value of . in addition expr1 And expr2 The data type can be one of the data types of the system ( Such as ：TEXT、INTEGER、FLOAT etc. ),expr1 and expr2 The data type of should be consistent .
If expr1 Not for NULL, The data type is the same as expr1; If expr1 by NULL, The data type is the same as expr2.
In terms of compatibility ,ISNULL amount to MSSQL 2005 Medium ISNULL function 、KingbaseES Medium NVL function 、ORACLE Medium NVL function .
Example ：
SELECT ISNULL('2001-01-10', TO_DATE('05 Dec 2000', 'DD Mon YYYY')) AS RESULT1,
       ISNULL(NULL, TO_DATE('05 Dec 2000', 'DD Mon YYYY')) AS RESULT2,
       ISNULL(NULL, 123) AS RESULT3, ISNULL(789, 123) AS RESULT4,
       ISNULL(NULL, '123') AS RESULT5;

8.174. ISOPEN

usage ：
isopen(path)
function ：
Geometric functions , Judge whether the parameter is an open path .
Example ：
isopen(path '[(0,0),(1,1),(2,0)]')

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