where-clause

问题 is have this statement and i want to make it by the Active Records way in codeigniter DELETE FROM TABLE (col1 = value AND col2 = value2 ) OR (col1 = value2 AND col2 = value ); 回答1: CodeIgniter Active Record is impractical for mixing AND's and OR's within a query. You will likely need to construct some of the query manually, e.g. something along the lines of: $this->db->where("col1 = $value AND col2 = $value2"); $this->db->or_where("col1 = $value2 AND col2 = $value"); Alternately, in your

问题 My SQL SELECT query has 3 variables set by a HTML form, however these variables can be null: $suburb = (isset($_POST['suburb'])) ? $_POST['suburb'] : ''; $postcode = (isset($_POST['postcode'])) ? $_POST['postcode'] : ''; $state = (isset($_POST['state'])) ? $_POST['state'] : ''; When all 3 variables are entered in the form the SELECT query processes fine (due to the AND's in the WHERE clause). But when one or more variables are blank, the SELECT query errors as it is looking for a NULL value

问题 My SQL SELECT query has 3 variables set by a HTML form, however these variables can be null: $suburb = (isset($_POST['suburb'])) ? $_POST['suburb'] : ''; $postcode = (isset($_POST['postcode'])) ? $_POST['postcode'] : ''; $state = (isset($_POST['state'])) ? $_POST['state'] : ''; When all 3 variables are entered in the form the SELECT query processes fine (due to the AND's in the WHERE clause). But when one or more variables are blank, the SELECT query errors as it is looking for a NULL value

问题 My SQL SELECT query has 3 variables set by a HTML form, however these variables can be null: $suburb = (isset($_POST['suburb'])) ? $_POST['suburb'] : ''; $postcode = (isset($_POST['postcode'])) ? $_POST['postcode'] : ''; $state = (isset($_POST['state'])) ? $_POST['state'] : ''; When all 3 variables are entered in the form the SELECT query processes fine (due to the AND's in the WHERE clause). But when one or more variables are blank, the SELECT query errors as it is looking for a NULL value

问题 I want to check if a boolean is true, then decide in the WHERE clause what condition to use. Say the boolean variable is @checkbool: SELECT * FROM TableA A WHERE --if @checkbool is true, run this A.Id = 123 --if @checkbool is false, run this A.Id <> 123 Is there a way to negate a condition? Like in C++ you can do if !(condition). If not, what is the best way to solve this problem? Thank you! 回答1: SQL's equivalent of ! in C is NOT . However, in your case you want something else: you need to

问题 I want to check if a boolean is true, then decide in the WHERE clause what condition to use. Say the boolean variable is @checkbool: SELECT * FROM TableA A WHERE --if @checkbool is true, run this A.Id = 123 --if @checkbool is false, run this A.Id <> 123 Is there a way to negate a condition? Like in C++ you can do if !(condition). If not, what is the best way to solve this problem? Thank you! 回答1: SQL's equivalent of ! in C is NOT . However, in your case you want something else: you need to

问题 I need that when I create a Historic do it: Table historic id authorization_origin_id 1 2 2 3 How you see in image bellow This is my new.html.erb <%= simple_form_for(@refinancing) do |f| %> <div class="form-inputs"> <%= f.hidden_field :employee_id, value: @employee.first.id %> <%= f.input :contract_number %> </div> <h3>Reserved value</h3> <table class="table table-condensed table-bordered table-striped"> <thead> <th>Authorization id</th> <th>Contract number</th> </thead> <% @authorizations

问题 I currently have the following code select * FROM list WHERE name LIKE '___' ORDER BY name; I am trying to get it so that it only shows names with three or more words. It only displays names with three characters I cannot seem to work out the correct syntax for this. Any help is appreciated Thankyou 回答1: If you assume that there are no double spaces, you can do: WHERE name like '% % %' To get names with three or more words. If you can have double spaces (or other punctuation), then you are

问题 I have a DataTable that I am pulling from a DataSet. From the DataTable, I want to use the Where clause to return a particular row. I looked at "How can I select a row from a datatable using two variable values?" but I get an error "Cannot implicitly convert type 'System.Data.DataRow[]' to 'System.Data.DataRow'" I searched google, but could not find a solution. My code is: mySqlDataAdapter.Fill(myDataSet); DataTable dtTable = myDataSet.Tables[0]; DataRow dr = dtTable.Select("VendorID = " +

问题 I have a DataTable that I am pulling from a DataSet. From the DataTable, I want to use the Where clause to return a particular row. I looked at "How can I select a row from a datatable using two variable values?" but I get an error "Cannot implicitly convert type 'System.Data.DataRow[]' to 'System.Data.DataRow'" I searched google, but could not find a solution. My code is: mySqlDataAdapter.Fill(myDataSet); DataTable dtTable = myDataSet.Tables[0]; DataRow dr = dtTable.Select("VendorID = " +