MySQL uses cursors to iterate through query result sets

/* We sometimes encounter the need to traverse and do some operations (such as insertions) of the records s_s from the result set queried by the a table, and the data required for these operations may be partially from the s_s collection */
/* Temporary stored procedures, no way, not directly in the query window to do these things. */
drop procedure ifexists proc_tmp; CREATE PROCEDURE proc_tmp ()BEGIN
/* This can be written as well: DECLARE done   INT  DEFAULT  FALSE  ; */declare doneint default 0; /* Used to determine whether to end the cycle */declare hostId bigint; /* is used to store the record of the result set s_s (because I have only one column and bigint type for the s_s record here) */
/* Define CURSOR */DECLARE idcur cursor  for SelectA.hostid fromDev_host asA, Sys_hostconfig asBwhereA.hostid! =B.hostid;
/* Define the logic to set the loop end to identify how the done value changed */declare Continue Handler  for  notFOUNDSetDone =1;/*done = true; also */open idcur;  /* OPEN cursor */REPEATfetch idcur into hostId;  /* This section can read the book and fetch multiple columns (assuming that the result set s_s record is not a single column) */ifThe   not  -done and/* values for non-0,mysql are considered true*/insert into Sys_hostconfig (HostId, Aeleccap, Beleccap, Celeccap, Remeleccap, Atmpcap, Btmpcap, Ctmpcap, Boxtmpcap, Createtime)
/* Note that this uses hostId and now () * *values(hostId, the, the, the, -, the, the, the, the, now ()); End if; until done end repeat;  Close idcur; /* Close the cursor */END call proc_tmp ();  drop procedure proc_tmp; /* Delete temporary stored procedures * /

MySQL uses cursors to iterate through query result sets