这里使用JavaScript生成复杂的SQL查询表单，运行一下就明白了，它可以根据选择的查询条件，自动修改你的SQL语句，是一个很典型的应用。
运行效果截图如下：
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>查询条件表单</title> <style> *{ font-size:12px; padding:0; margin:0; } body{ padding:40px; } #MainBox{ border:#666 1px solid; background-color:#eee; width:700px; } #MainBox td{ padding:4px; } #ConditionBox{ height:150px; width:100%; overflow-y:auto; border:#bbb 1px solid; padding:2px; background-color:#fff; } .tmFrame{ border:#eee 1px solid; padding:2px; width:100%; } .tmFrame_highlight{ border:#666 1px solid; padding:2px; width:100%; background-color:#f7f7f7; } .fname{ float:left; width:200px; } .conn{ float:left; width:100px; } .fvalue{ float:left; width:100px; } .handlebox{ float:right; width:180px; display:none; } .handlebox_view{ float:right; width:180px; display:block; } .rbox{ float:right; margin:1px; background-color:#999; color:#fff; padding:1px; width:15px; cursor:hand; } legend{ border:#bbb 1px solid; padding:4px; } fieldset{ border:#bbb 1px solid; padding:4px; } .sqlwords{ margin:2px; border:#bbb 1px solid; width:100%; } </style> <script> ////构造函数 function ce(e){return document.createElement(e)} /* Example: * var a = cex("DIV", {onmouseover:foo, name:'div1', id:'main'}); */ function cex(e, x){ var a = ce(e); for (prop in x){ a[prop] = x[prop]; } return a; } /* * function ge * Shorthand function for document.getElementById(i) */ function ge(i){return document.getElementById(i)} /* * function ac * Example: ac( house, ac(roof, shingles), ac(floor, ac(tiles, grout))) */ function ac(){ if (ac.arguments.length > 1){ var a = ac.arguments[0]; for (i=1; i<ac.arguments.length; i++){ if (arguments[i]) a.appendChild(ac.arguments[i]); } return a; } else { return null; } } /////ID增量 function guid(){ if (!window.__id) window.__id = 0; return ++window.__id; } //======建立条件类 function term(tname,fname,conn,fvalue,ttype){ this.tname=tname; this.fname=fname; this.conn=conn; this.fvalue=fvalue; this.id= guid(); this.ttype=ttype; } term.prototype.getHTML = function(){ var termFrame = cex("DIV", { id:this.id, className:'tmframe', onmouseover:this.fc_term_onmouseover(), onmouseout:this.fc_term_onmouseout() }); //var module = cex("DIV", { //id:'module'+this.id, //className:'module' //}); var tttt=this.tname+"."+this.fname; if(this.ttype!='fset') tttt=this.tname; var mtt = cex("input", { id:'tp'+this.id, name:'fname'+this.id, type:"hidden", value:this.ttype }); var fname = cex("DIV", { id:'fname'+this.id, className:'fname', innerHTML:tttt }); var conn = cex("DIV", { id:'conn'+this.id, className:'conn', innerHTML:this.conn }); var fvalue = cex("DIV", { id:'fvalue'+this.id, className:'fvalue', innerHTML:this.fvalue }); var handlebox = cex("div", { id:'handlebox'+this.id, className:"handlebox" }); var mdel = cex("div", { id:'tmdel'+this.id, onclick:this.fc_mdel_onclick(), className:"rbox", title:"删除此条件", innerHTML: 'X' }); var mup = cex("div", { id:'tmup'+this.id, onclick:this.fc_mup_onclick(), className:"rbox", title:"向上移动", innerHTML: '↑' }); var mdown = cex("div", { id:'tmdown'+this.id, onclick:this.fc_mdown_onclick(), className:"rbox", title:"向下移动", innerHTML: '↓' }); var mzkh = cex("div", { id:'tzkh'+this.id, onclick:this.fc_mzkh_onclick(), className:"rbox", title:"添加左括号", innerHTML: '(' }); var mykh = cex("div", { id:'tykh'+this.id, onclick:this.fc_mykh_onclick(), className:"rbox", title:"添加右括号", innerHTML: ')' }); var mand = cex("div", { id:'tand'+this.id, onclick:this.fc_mand_onclick(), className:"rbox", title:"添加并条件", innerHTML: 'and' }); var mor = cex("div", { id:'tor'+this.id, onclick:this.fc_mor_onclick(), className:"rbox", title:"添加或条件", innerHTML: 'or' }); // Build DIV ac (termFrame, mtt, ac (handlebox, mdel, mup, mdown, mykh, mzkh, mand, mor ), fname, conn, fvalue ); return termFrame; } term.prototype.highlight = function(){ ge("handlebox"+this.id).className = 'handlebox_view'; ge(this.id).className = 'tmFrame_highlight'; } term.prototype.lowlight = function(){ ge("handlebox"+this.id).className = 'handlebox'; ge(this.id).className = 'tmFrame'; } term.prototype.remove = function(){ var _this = ge(this.id); _this.parentNode.removeChild(_this); } term.prototype.moveup = function(){ var _this = ge(this.id); var pre_this = _this.previousSibling; if(pre_this!=null){ _this.parentNode.insertBefore(_this,pre_this); this.lowlight(); } } term.prototype.movedown = function(){ var _this = ge(this.id); var next_this = _this.nextSibling; if(next_this!=null){ _this.parentNode.insertBefore(next_this,_this); this.lowlight(); } } term.prototype.addzkh = function(){ var _this = ge(this.id); var tzkh = new term('╭----------------','','','','zkh'); var node_zkh = tzkh.getHTML(); _this.parentNode.insertBefore(node_zkh,_this); } term.prototype.addykh = function(){ var _this = ge(this.id); var tykh = new term('╰----------------','','','','ykh'); var node_ykh = tykh.getHTML(); if(_this.nextSibling!=null) _this.parentNode.insertBefore(node_ykh,_this.nextSibling); else _this.parentNode.appendChild(node_ykh); } term.prototype.addand = function(){ var _this = ge(this.id); var tand = new term(' 并且','','','','tand'); var node_and = tand.getHTML(); if(_this.nextSibling!=null) _this.parentNode.insertBefore(node_and,_this.nextSibling); else _this.parentNode.appendChild(node_and); } term.prototype.addor = function(){ var _this = ge(this.id); var tor = new term(' 或者','','','','tor'); var node_or = tor.getHTML(); if(_this.nextSibling!=null) _this.parentNode.insertBefore(node_or,_this.nextSibling); else _this.parentNode.appendChild(node_or); } ///对象控制函数 term.prototype.fc_term_onmouseover = function(){ var _this = this; return function(){ //if (!_this.isDragging) _this.highlight(); } } term.prototype.fc_term_onmouseout = function(){ var _this = this; return function(){ //if (!_this.isDragging) _this.lowlight(); } } term.prototype.fc_mdel_onclick = function(){ var _this = this; return function(){ _this.remove(); } } term.prototype.fc_mup_onclick = function(){ var _this = this; return function(){ _this.moveup(); } } term.prototype.fc_mdown_onclick = function(){ var _this = this; return function(){ _this.movedown(); } } term.prototype.fc_mzkh_onclick = function(){ var _this = this; return function(){ _this.addzkh(); } } term.prototype.fc_mykh_onclick = function(){ var _this = this; return function(){ _this.addykh(); } } term.prototype.fc_mand_onclick = function(){ var _this = this; return function(){ _this.addand(); } } term.prototype.fc_mor_onclick = function(){ var _this = this; return function(){ _this.addor(); } } /////插入页面 function insertterm(){ var tname = document.all.tname.value; var fname = document.all.fname.value; var conn = document.all.conn.value; var fvalue = document.all.fvalue.value; //xl(tname+"|"+fname+"|"+conn+"|"+fvalue); var tm = new term(tname,fname,conn,fvalue,"fset"); var tmHTML = tm.getHTML(); ac(ge("ConditionBox"),tmHTML); //ZA.addterm(tm); addtofrom(tname); } var tt = new Array(); function addtofrom(tname){ var ttexit="no"; for(var i=0;i<tt.length;i++){ if(tt[i]==tname) ttexit="yes"; } if(ttexit=="no"){ tt[i]=tname; //alert(tt[i]); } } //====条件控制窗口函数 function CBadd(){ var h = document.all.ConditionBox.offsetHeight; document.all.ConditionBox.style.height = h + 20 + "px"; } function CBcut(){ var h = document.all.ConditionBox.offsetHeight; if(h>=150) document.all.ConditionBox.style.height = h - 20 + "px"; else return false; } function getSQL(){ var sql=""; var ma = ge("ConditionBox").childNodes; for(i=0;i<ma.length;i++){ var id = ma[i].getAttribute("id"); var tp = ge("tp"+id).value; if(tp=="fset"){ //sql+=" "+ge("fname"+id).innerHTML; //sql+=" "+ge("conn"+id).innerHTML; //sql+=" \""+ge("fvalue"+id).innerHTML+"\""; var fname=ge("fname"+id).innerHTML; var conn=ge("conn"+id).innerHTML; var fvalue=ge("fvalue"+id).innerHTML; sql+=" "+fname; if(conn=="等于") sql+=" = "+"\'"+fvalue+"\'"; if(conn=="大于") sql+=" > "+"\'"+fvalue+"\'"; if(conn=="小于") sql+=" < "+"\'"+fvalue+"\'"; if(conn=="不等于") sql+=" <> "+"\'"+fvalue+"\'"; if(conn=="为空") sql+=" is null "; if(conn=="不为空") sql+=" is not null "; if(conn=="包含") sql+=" like \'%"+fvalue+"%\'"; } else{ //sql+=" "+ge("fname"+id).innerHTML; if(tp=="zkh") sql+=" ("; if(tp=="ykh") sql+=" )"; if(tp=="tand") sql+=" and"; if(tp=="tor") sql+=" or"; } //var mn = ma.childNodes; } var ffrom = "FROM "+getFrom(); ge("sqlwords").value ="Select * "+ ffrom+" Where "+sql; } function getFrom(){ var ff=tt.toString(); return ff; } </script> </head> <body> <table cellspacing="0" cellpadding="0"> <tr> <td colspan="2">复杂查询表单</td> </tr> <tr> <td><div></div> <div><SPAN title='放大显示框'>6</SPAN><SPAN title='缩小显示'>5</SPAN></div></td> </tr> <tr> <td> <fieldset> <legend>SQL表达式</legend> <input type="text" /><input type="submit" value="GET SQL"/> </fieldset> </td> </tr> <tr> <td> <fieldset> <legend>定义条件</legend> <table cellspacing="0" cellpadding="0"> <tr> <td>表</td> <td><select> <option value="table1" selected="selected">表1</option> <option value="table2">表2</option> <option value="table3">表3</option> <option value="table4">表4</option> <option value="table5">表5</option> </select></td> <td>字段</td> <td><select> <option value="f1">字段1</option> <option value="f2">字段2</option> <option value="f3">字段3</option> <option value="f4">字段4</option> <option value="f5">字段5</option> <option value="f6">字段6</option> <option value="f7">字段7</option> </select></td> <td>关系</td> <td><select> <option value="大于">大于</option> <option value="等于">等于</option> <option value="小于">小于</option> <option value="不等于">不等于</option> <option value="为空">为空</option> <option value="不为空">不为空</option> <option value="包含">包含</option> </select></td> <td>值</td> <td><input type="text" value="111111" /></td> <td><input type="submit" value="增加新条件"/></td> </tr> </table> </fieldset> </td> </tr> </table> </body> </html>