query_string=0x1ab31b8 "select * from test_policy ;", paramTypes=0x0, numParams=0, queryEnv=0x0) at postgres.c:666 如上面堆栈信息所示,在QueryRewrite阶段,fireRIRrules函数中,会调用get_row_security_policies,将当前表达式添加到rte->securityQuals字段中,并且设置 parsetree->hasRowSecurity = true...
Input/Output \copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \i FILE execute commands from file \ir FILE as \i, but relative to location of current script \o [FILE] send all query results to file or |pipe \qecho [STRIN...
CREATEORREPLACEFUNCTIONfuncname ( in_idinteger)RETURNSSETOFvarcharas$$DECLAREv_rec RECORD;BEGINreturnquery ( (selectnamefromtest_result1whereid=in_id)union(selectnamefromtest_result2whereid=in_id) );return;END; $$ LANGUAGE PLPGSQL; 注意:如果 返回类型为 setof,最好用如下方法 RETURNQUERYEXECUTESQ...
EXECUTE FUNCTION trigger_function;其中,event 可以是 INSERT、UPDATE、DELETE 或者 TRUNCATE,UPDATE 支持特定字段(UPDATE OF col1, clo2)的更新操作;触发器可以在事件之前(BEFORE)或者之后(AFTER)触发,INSTEAD OF 只能用于替代视图上的 INSERT、UPDATE 或者 DELETE 操作;FOR EACH ROW 表示行级触发器,FOR EACH STATEME...
RETURNQUERYEXECUTESQL 不要这么用 executesqlinto out;returnout; 返回多行多列 也有多种方式 1. 使用 return next 和 setof record ,需要 for 循环 CREATEORREPLACEFUNCTIONfuncname ( in_idinteger)RETURNSSETOF RECORDas $$DECLARE v_rec RECORD; BEGINforv_recin( (selectid , namefromtest_result1where...
RETURNQUERYEXECUTESQL 不要这么用 executesqlintoout;returnout; 返回多行多列 也有多种方式 1. 使用 return next 和 setof record ,需要 for 循环 CREATEORREPLACEFUNCTIONfuncname ( in_idinteger)RETURNSSETOF RECORDas$$DECLAREv_rec RECORD;BEGINforv_recin( (selectid , namefromtest_result1whereid=in...
1、StringInfoData/*--- * StringInfoData holds information about an extensible string. * data is the current buffer for the string (allocated with palloc). * len is the current string length. There is guaranteed to be * a terminating '\0' at data[len], although this i...
是指在PostgreSQL数据库中进行左连接查询时,右表的连接条件与左表的连接条件不匹配,导致连接操作无法完成。 左连接是一种常见的关联查询方式,它返回左表中的所有记录,以及与右表中匹配的记录。在执...
completionTag=<optimized out>) at pquery.c:1143 #12 0x0000000000b9de58 in exec_simple_query (query_string=<optimized out>) at postgres.c:1685 #13 0x0000000000b9f8cc in PostgresMain (argc=<optimized out>, argv=argv@entry=0x18f0a50, dbname=<optimized out>, username=<optimized out>) at...
Advanced query methods Cursors await sql``.cursor([rows = 1], [fn]) Use cursors if you need to throttle the amount of rows being returned from a query. You can use a cursor either as anasync iterableor with a callback function. For a callback function new results won't be requested...