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This function starts a database query using the supplied connection. Use the returned query handle with dbPoll to get the result, or dbFree if you don't want the result.

Tip

The server command debugdb 2 will output verbose information on each query to a logging file (usually logs/db.log )

Important

It is strongly recommended to use this function asynchronously, as presented in "This example starts a select query and processes the result in an inline callback function with custom arguments:"

OOP Syntax Help! I don't understand this!

• Method: connection:query(...)

Syntax

handle dbQuery ( function callbackFunction, [ table callbackArguments, ], element databaseConnection, string query, var param1 [, var param2 ...] )

Required Arguments

• callbackFunction: An optional function to be called when a result is ready. The function will only be called if the result has not already been read with dbPoll . The function is called with the query handle as the first argument.
• table callbackArguments, ]: MISSING_PARAM_DESC
• databaseConnection: A database connection element previously returned from dbConnect
• query: An SQL query. Positions where parameter values will be inserted are marked with a ?
• param1 [, var param2 ...]: MISSING_PARAM_DESC

Returns

• handle: value

Returns a query handle unless the connection is incorrect, in which case it return false .

Code Examples

Example 1 Example 2 Example 3 Example 4 Example 5

shared

This example starts an INSERT query and frees the result:

local qh = dbQuery( connection, "INSERT INTO table_name VALUES (?,?,?)", "aaa", "bbb", 10 )
dbFree( qh )

shared

This example starts a select query and waits for the result: (server freeze included)

local qh = dbQuery( connection, "SELECT * FROM table_name" )
local result = dbPoll( qh, -1 )

shared

This example starts a select query and processes the result in a callback function:

function aaa()
    dbQuery( myCallback, connection, "SELECT * FROM table_name" )
end

function myCallback(qh)
    local result = dbPoll( qh, 0 )   -- Timeout doesn't matter here because the result will always be ready
end

shared

This example starts a select query and processes the result in an inline callback function with custom arguments:

dbQuery( function(qh, tag, score)
            local result = dbPoll( qh, 0 )   -- Timeout doesn't matter here because the result will always be ready
            outputDebugString( tag )         -- Prints "hello"
            outputDebugString( score )       -- Prints 2000
         end
         ,{"hello",2000}, connection, "SELECT * FROM table_name" )

shared

This example shows how to use backticks and??for parts of the query that are not column values:

dbExec( connection, "UPDATE `??` SET `??`=?", tableName, columnName, columnValue )

See Also

Database Functions

• dbConnect
• dbExec
• dbFree
• dbPoll
• dbPrepareString
• dbQuery
• executeSQLQuery

Reference

• Scripting Functions