I have a big, ugly query which is quadratic in the input size and therefore want to display an approximate completion time prior to sending it off:
Syntactically this is wrong and is merely illustrative. There is no FROM clause, so I cannot use a traditional subquery. How would this be programmed in MySQL 5.7?
Hi there,
I have a hierarchical database that include 4 tables. Table A is the parent of B, B is Parent of C, C is parent of D. If I want to query everything in D that is associated with A.name, how do I do that? Thanks!
YanYan (0 Replies)
Hi there, I have a table that stores multiple records for many different servers, each of which is timestamped ... I wanted to write a query that would enable me to only output the "latest" record (based on timestamp) for each "unique" server. So for example my main table looks like this
... (3 Replies)
hello all
i have 2 columns every column in the following format
column1
2011-04-01 11:39:54
column2
2019-02-03 00:00:00
i want get difference between above data as following
2 days 11:39
how to do so ?
i tried many functions but nothing works
please advice what is the query... (6 Replies)
Hi,
I want to access mysql query from database , for that i have tried the below code
#! /bin/bash
TABLE_NAME=database1
USER_NAME=root
IP_ADDR=111.20.9.256
somevar=`echo "select altid from alert where altid='2724'"| mysql -h $IP_ADDR -u $USER_NAME $TABLE_NAME `
echo $somevar
... (1 Reply)
Hi,
I want to run below query on shellscript but having one problm.
ADV=$( mysql -h "$IP_ADDR" -u "$USER_NAME" "$TABLE_NAME" -BNe" SELECT ADV FROM indata where inid='$INSTRUID' and Date='$latest Date';" )
here Date column contans different below dates
2011-12-01... (0 Replies)
Hi,
I want to run below query on shellscript but having one problm.
ADV=$( mysql -h "$IP_ADDR" -u "$USER_NAME" "$TABLE_NAME" -BNe" SELECT ADV FROM indata where inid='$INSTRUID' and Date='$latest Date';" )
here Date column contans different below dates
2011-12-01... (11 Replies)
Hello
i have created mysql query to compare to values and get difference in percentage
as following:
SELECT file_name, 100 - ((100 * (SELECT file_count FROM xipi_files z WHERE x.file_group = z.file_group AND x.file_name = z.file_name AND z.insert_date = CURDATE( ) - INTERVAL 1 DAY)) /... (1 Reply)
Hi All,
i have a table in mysql with the following data
Table name Test
Assettype Serial_No Status location
Mouse 123456 In Stock chennai
Mouse 98765 Allocated chennai
Keyboard ... (2 Replies)
Discussion started by: venkitesh
2 Replies
LEARN ABOUT PHP
mysqlnd_ms_query_is_select
MYSQLND_MS_QUERY_IS_SELECT(3) 1 MYSQLND_MS_QUERY_IS_SELECT(3)mysqlnd_ms_query_is_select - Find whether to send the query to the master, the slave or the last used MySQL serverSYNOPSIS
int mysqlnd_ms_query_is_select (string $query)
DESCRIPTION
Finds whether to send the query to the master, the slave or the last used MySQL server.
The plugins built-in read/write split mechanism will be used to analyze the query string to make a recommendation where to send the query.
The built-in read/write split mechanism is very basic and simple. The plugin will recommend sending all queries to the MySQL replication
master server but those which begin with SELECT, or begin with a SQL hint which enforces sending the query to a slave server. Due to the
basic but fast algorithm the plugin may propose to run some read-only statements such as SHOW TABLES on the replication master.
PARAMETERS
o $query
- Query string to test.
RETURN VALUES
A return value of MYSQLND_MS_QUERY_USE_MASTER indicates that the query should be send to the MySQL replication master server. The function
returns a value of MYSQLND_MS_QUERY_USE_SLAVE if the query can be run on a slave because it is considered read-only. A value of
MYSQLND_MS_QUERY_USE_LAST_USED is returned to recommend running the query on the last used server. This can either be a MySQL replication
master server or a MySQL replication slave server.
If read write splitting has been disabled by setting mysqlnd_ms.disable_rw_split, the function will always return
MYSQLND_MS_QUERY_USE_MASTER or MYSQLND_MS_QUERY_USE_LAST_USED.
EXAMPLES
Example #1
mysqlnd_ms_query_is_select(3) example
<?php
function is_select($query)
{
switch (mysqlnd_ms_query_is_select($query))
{
case MYSQLND_MS_QUERY_USE_MASTER:
printf("'%s' should be run on the master.
", $query);
break;
case MYSQLND_MS_QUERY_USE_SLAVE:
printf("'%s' should be run on a slave.
", $query);
break;
case MYSQLND_MS_QUERY_USE_LAST_USED:
printf("'%s' should be run on the server that has run the previous query
", $query);
break;
default:
printf("No suggestion where to run the '%s', fallback to master recommended
", $query);
break;
}
}
is_select("INSERT INTO test(id) VALUES (1)");
is_select("SELECT 1 FROM DUAL");
is_select("/*" . MYSQLND_MS_LAST_USED_SWITCH . "*/SELECT 2 FROM DUAL");
?>
The above example will output:
INSERT INTO test(id) VALUES (1) should be run on the master.
SELECT 1 FROM DUAL should be run on a slave.
/*ms=last_used*/SELECT 2 FROM DUAL should be run on the server that has run the previous query
SEE ALSO
Predefined Constants, user filter .Runtime configuration, mysqlnd_ms.disable_rw_split, mysqlnd_ms.enable.
PHP Documentation Group MYSQLND_MS_QUERY_IS_SELECT(3)