“ where 1 = 1”的陈述[重复]

通常是在人们建立SQL语句时。

添加时，

and value = "Toyota"

没有魔力，只有实用

示例代码：

commandText = "select * from car_table where 1=1";if (modelYear <> 0)     commandText += " and year="+modelYearif (manufacturer <> "") commandText += " and value="+QuotedStr(manufacturer)if (color <> "")        commandText += " and color="+QuotedStr(color)if (california)         commandText += " and hasCatalytic=1"

否则，您将必须具有一组复杂的逻辑：

commandText = "select * from car_table"whereClause = "";if (modelYear <> 0){   if (whereClause <> "")       whereClause = whereClause + " and ";   commandText += "year="+modelYear;}if (manufacturer <> ""){       if (whereClause <> "")       whereClause = whereClause + " and ";   commandText += "value="+QuotedStr(manufacturer)}if (color <> ""){   if (whereClause <> "")       whereClause = whereClause + " and ";   commandText += "color="+QuotedStr(color)}if (california){   if (whereClause <> "")       whereClause = whereClause + " and ";   commandText += "hasCatalytic=1"}if (whereClause <> "")   commandText = commandText + "WHERe "+whereClause;