BEGIN

SET @baseStr= "SELECT * FROM tbName WHERE 1=1 ";

SET @_where="";

IF 1=1 THEN

　　SET @_where= CONCAT(@_where," AND sourcedomain=\"www.baidu.com\" ");

END IF;

IF 2=2 THEN

　　SET @_where=CONCAT(@_where," AND userId =4444");

END IF;

  SET @sentence =CONCAT(@baseStr,@_where) ; -- 连接字符串生成要执行的SQL语句

  prepare stmt from @sentence; -- 预编释一下。 “stmt”预编释变量的名称，

  execute stmt; -- 执行SQL语句

  deallocate prepare stmt;    -- 释放资源

END

SET @_rowCount=0; -- 变量

SET @_count =CONCAT("SELECT COUNT(*) INTO @_rowCount ",@baseStr,@_where);

prepare stmt from @_count;

execute stmt;

deallocate prepare stmt;

SET _pageCount=@_rowCount;