Note: to enter an input message and error alert message, go to the Input Message and Error Alert tab. You've already entered that invoice number. Again, this value may only occur once (=1) since we don't want duplicate entries. To check this, select cell A3 and click Data Validation.Īs you can see, this function counts the number of values in the range A2:A20 that are equal to the value in cell A3.
Notice how we created an absolute reference ($A$2:$A$20) to fix this reference.ĥ. Because we selected the range A2:A20 before we clicked on Data Validation, Excel automatically copies the formula to the other cells. Using conditional formatting to highlight a row. This step by step tutorial will assist all levels of Excel users in highlighting rows or columns based on a condition.
This value may only occur once (=1) since we don't want duplicate entries. There are instances when we need to highlight a row or a column, depending on the data we have and the desired results. =COUNTIF($A$2:$A$20,A2) counts the number of values in the range A2:A20 that are equal to the value in cell A2. In the Formula box, enter the formula shown below and click OK.Įxplanation: The COUNTIF function takes two arguments. On the Data tab, in the Data Tools group, click Data Validation.Ĥ.
