GeezerVison

The simplest option is to use the conditional with the CSS "display:none" property:

{| class="wikitable"
|- {{#if: {{{variable_foo|}}} | | style="display: none;" }}
! Foo
| {{{variable_foo}}}
|-
! Bar
| {{{variable_bar}}}
|}

The code above is in {{Conditional tables/example 2c}}. The table below demonstrates the effect when it is used:

Pros and cons: with this method, there is no need for the wikitable pipe character to appear in the #if conditional, thus avoiding issues with escaping the vertical bar . However, sources and notes referred to in the hidden cells won't get suppressed with the other contents, so they will continue to be listed at the end of an article without any references to them occurring in the article's text.

One method of hiding rows in tables (or other structures within tables) uses HTML directly.^[1] In general, there are only a handful of HTML tags you need to be aware of

• <tr> - this tag creates a new row (similar to |- in MediaWiki table syntax)
• <th> - this tag creates a new header cell within a row (similar to ! in MediaWiki table syntax)
• <td> - this tag creates a new cell within a row (similar to | in MediaWiki table syntax)
• <caption> - this tag creates a caption (similar to |+ in MediaWiki table syntax)

A sample HTML table with a conditional row based on testing a template variable with #if follows:

{| class="wikitable"
{{#if:{{{variable_foo|}}}
|<tr><th>Foo</th><td>{{{variable_foo}}}</td></tr>}}
|-
! Bar
| {{{variable_bar}}}
|}

The code above is in {{Conditional tables/example 2a}}. As before, the table below demonstrates the effect when it's used:

Because the parser function #if and MediaWiki table syntax do not work together well, the template code described at § Pitfalls with an illustration of non-working code at Example 2 will not work correctly. The problems there can be rectified by properly escaping the vertical bar.

For most characters, often it's good enough to replace a problematic characters with the corresponding HTML entities, e.g. "{" by {, "|" by |, and "}" by }. But for Wiki tables a real vertical bar character "|" is required — using | HTML entity does not work.

A simple trick allows to protect the "|" in template parameter values while still arriving as real "|" delimiter in the Wiki table, see the magic word {{!}}. Note that "!" (exclamation mark) has no problems with templates, it's the other delimiter used in Wiki tables. Here's the code for plan B:

{| class="wikitable"
{{#if:{{{foo|}}}|
{{!}}-
! Foo
{{!}} {{{foo}}}
}}
|-
! Bar
| {{{bar}}}
|}

The code above is in {{Conditional tables/example 2b}}. As before, the table below demonstrates the effect when it's used: